Synthesis of halichondrin analogs and uses thereof

ABSTRACT

The present invention provides halichondrin analogs, such as compounds of Formula (I). The compounds may bind to microtubule sites, thereby inhibiting microtubule dynamics. Also provided are methods of synthesis, pharmaceutical compositions, kits, methods of treatment, and uses that involve the compounds for treatment of a proliferative disease (e.g., cancer). Compounds of the present invention are particularly useful for the treatment of metastatic breast cancer, non-small cell lung cancer, prostate cancer, and sarcoma. The included methods of synthesis are useful for the preparation of compounds of Formula (I)-(III) along with naturally occurring halicondrins (e.g., halichondrin B &amp; C, norhalichondrin A, B, &amp; C, and homohalichondrin A, B, &amp; C). Also included are methods for interconverting between the halichondrins, norhalichondrins, and homohalichondrins and their unnatural epimers at the C38 ketal stereocenter through the use of an acid-mediated equilibration.

RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. §119(e) to U.S.provisional patent application, U.S. Ser. No. 62/019,224, filed Jun. 30,2014, which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

The halichondrins are polyether macrolides, originally isolated from themarine sponge Halichondria okadai by Uemura, Hirata, and coworkers.Several additional members, including halistatin, were also isolatedfrom marine sponges. This class of natural products displays interestingstructural diversity at two main sites, one being the oxidation state atC10, C12, and C13 of the C8-C14 polycycle, and the other being thelength of the carbon backbone. Based on the elements providingstructural diversity, this class of natural products has been groupedinto the norhalichondrin, halichondrin, and homohalichondrin series withseveral representative sub-groups (see FIG. 1). While norhalichondrinsA-C, homohalichondrins A-C, and halichondrins B & C have all beenisolated from the natural sources, halichondrin A has never beenisolated from natural sources.

Due to their intriguing structural architecture and extraordinary invitro and in vivo anti-proliferative activity, the halichondrins havereceived much attention from the scientific community. Indeed, Eisairecently received FDA approval for the halichondrin derivative eribulin(HALAVEN®) for treatment of metastatic breast cancer, furtherhighlighting the importance these natural products derivatives. Thus,further research focused on the discovery of novel agents within thisstructural class is likely to provide new anti-proliferative agents withimproved efficacy or safety. Furthermore, new synthetic methods thatstreamline the preparation of these natural products or relatedderivatives are important given the structural complexity of thehalichondrin backbone.

SUMMARY OF THE INVENTION

The present invention provides the synthesis of halichondrin A andanalogs of Formula (I):

and pharmaceutically acceptable salts thereof, wherein R^(P1), R^(P2),R^(P3), R¹, R², R³, R⁴, R⁵, R⁶, R^(X), and R^(Y) are described herein.

In another aspect, the present invention provides the synthesis ofanalogs of norhalichondrin A and homohalichondrin A of Formula (II) and(III), respectively:

and pharmaceutically acceptable salts thereof, wherein R^(P8), R^(P12),R^(P13), R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R^(X), and R^(Y) are describedherein.

In another aspect, the present invention provides methods of preparingcompounds of Formula (I)-(III) and intermediates thereto, includingcompounds of Formula (A-1)-(L-1) as described herein.

In another aspect, the present invention provides methods forinterconverting between the halichondrins, norhalichondrins, andhomohalichondrins, and their unnatural epimers at the C38 ketalstereocenter through the use of an acid-mediated equilibration (see FIG.2).

In another aspect, the present invention provides the followingcompounds and methods for their preparation:

In another aspect, the present invention provides methods of preparingany one of the following compounds:

In another aspect, provided are pharmaceutical compositions comprising acompound of Formula (I)-(III) and optionally a pharmaceuticallyacceptable excipient. In certain embodiments, the pharmaceuticalcomposition is useful for treating and/or preventing a proliferativedisease (e.g., cancer) in a subject in need thereof. In certainembodiments, the method includes administering to the subject a compounddescribed herein, or a pharmaceutical composition thereof, in an amountsufficient to treat and/or prevent a proliferative disease.

In another aspect, provided are kits comprising a container with acompound described herein, or a pharmaceutical composition thereof. Thekits may include a single dose or multiple doses of a compound describedherein or a pharmaceutical composition thereof. The kits may also beuseful for treating and/or preventing a proliferative disease (e.g.,cancer) in a subject in need thereof. In certain embodiments, the kitsfurther include instructions for using the kit (e.g., for administeringa compound described herein, or a pharmaceutical composition thereof).

The details of certain embodiments of the invention are set forth in theDetailed Description of Certain Embodiments of the Invention, asdescribed below. Other features, objects, and advantages of theinvention will be apparent from the Claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the various sub-classes of halichondrins, norhalichondrins,and homohalichondrins. Norhalichondrins A-C, homohalichondrins A-C, andhalichondrins B & C are known natural products, while halichondrin A hasnever been isolated from a natural source.

FIG. 2 shows the interconversion of halichondrin A and its C38 epimer.Conditions have been developed that favor formation of either of theepimers.

FIG. 3 shows a possible mechanism for the observed solvent-dependent[5,5]-spiroketal equilibration at C38.

FIG. 4 shows proton chemical shift differences between halichondrin A,norhalichondrin A, and homohalichondrin A. The x-axis represents carbonnumber at which protons in question are attached. The y-axis showsproton chemical shift differences in ppm: dark gray: Δδ=(norhalichondrinA)−(synthetic halichondrin A); light gray: Δδ=(synthetic halichondrinA)−(homohalichondrin A). *methyl group attached at the indicated carbon;**exo-methylene group attached at the indicated carbon.

FIG. 5 shows proton chemical shift differences between halichondrin A,halichondrin B, and halichondrin C. The x-axis represents carbon numberat which protons in question are attached. The y-axis shows protonchemical shift differences in ppm: dark gray: Δδ=(synthetic halichondrinA)−(halichondrin B); light gray: Δδ=(halichondrin C)−(synthetichalichondrin A). *methyl group attached at the indicated carbon;**exo-methylene group attached at the indicated carbon.

DEFINITIONS Chemical Definitions

Definitions of specific functional groups and chemical terms aredescribed in more detail below. The chemical elements are identified inaccordance with the Periodic Table of the Elements, CAS version,Handbook of Chemistry and Physics, 75^(th) inside cover, and specificfunctional groups are generally defined as described therein.Additionally, general principles of organic chemistry, as well asspecific functional moieties and reactivity, are described in OrganicChemistry, Thomas Sorrell, University Science Books, Sausalito, 1999;Smith and March March's Advanced Organic Chemistry, 5^(th) Edition, JohnWiley & Sons, Inc., New York, 2001; Larock, Comprehensive OrganicTransformations, VCH Publishers, Inc., New York, 1989; and Carruthers,Some Modern Methods of Organic Synthesis, 3^(rd) Edition, CambridgeUniversity Press, Cambridge, 1987.

Compounds described herein can comprise one or more asymmetric centers,and thus can exist in various stereoisomeric forms, e.g., enantiomersand/or diastereomers. For example, the compounds described herein can bein the form of an individual enantiomer, diastereomer or geometricisomer, or can be in the form of a mixture of stereoisomers, includingracemic mixtures and mixtures enriched in one or more stereoisomer.Isomers can be isolated from mixtures by methods known to those skilledin the art, including chiral high pressure liquid chromatography (HPLC)and the formation and crystallization of chiral salts; or preferredisomers can be prepared by asymmetric syntheses. See, for example,Jacques et al., Enantiomers, Racemates and Resolutions (WileyInterscience, New York, 1981); Wilen et al., Tetrahedron 33:2725 (1977);Eliel, E. L. Stereochemistry of Carbon Compounds (McGraw-Hill, NY,1962); and Wilen, S. H. Tables of Resolving Agents and OpticalResolutions p. 268 (E. L. Eliel, Ed., Univ. of Notre Dame Press, NotreDame, Ind. 1972). The disclosure additionally encompasses compounds asindividual isomers substantially free of other isomers, andalternatively, as mixtures of various isomers.

The term “heteroatom” refers to an atom that is not hydrogen or carbon.In certain embodiments, the heteroatom is nitrogen. In certainembodiments, the heteroatom is oxygen. In certain embodiments, theheteroatom is sulfur.

When a range of values is listed, it is intended to encompass each valueand sub-range within the range. For example “C₁₋₆ alkyl” is intended toencompass, C₁, C₂, C₃, C₄, C₅, C₆, C₁₋₆, C₁₋₅, C₁₋₄, C₁₋₃, C₁₋₂, C₂₋₆,C₂₋₅, C₂₋₄, C₂₋₃, C₃₋₆, C₃₋₅, C₃₋₄, C₄₋₆, C₄₋₅, and C₅₋₆ alkyl.

The term “aliphatic” refers to alkyl, alkenyl, alkynyl, and carbocyclicgroups. Likewise, the term “heteroaliphatic” refers to heteroalkyl,heteroalkenyl, heteroalkynyl, and heterocyclic groups.

The term “alkyl” refers to a radical of a straight-chain or branchedsaturated hydrocarbon group having from 1 to 10 carbon atoms (“C₁₋₁₀alkyl”). In some embodiments, an alkyl group has 1 to 9 carbon atoms(“C₁₋₉ alkyl”). In some embodiments, an alkyl group has 1 to 8 carbonatoms (“C₁₋₈ alkyl”). In some embodiments, an alkyl group has 1 to 7carbon atoms (“C₁₋₇ alkyl”). In some embodiments, an alkyl group has 1to 6 carbon atoms (“C₁ ₆ alkyl”). In some embodiments, an alkyl grouphas 1 to 5 carbon atoms (“C₁ ₅ alkyl”). In some embodiments, an alkylgroup has 1 to 4 carbon atoms (“C₁₋₄ alkyl”). In some embodiments, analkyl group has 1 to 3 carbon atoms (“C₁₋₃ alkyl”). In some embodiments,an alkyl group has 1 to 2 carbon atoms (“C₁₋₂ alkyl”). In someembodiments, an alkyl group has 1 carbon atom (“C₁ alkyl”). In someembodiments, an alkyl group has 2 to 6 carbon atoms (“C₂ ₆ alkyl”).Examples of C₁ ₆ alkyl groups include methyl (C₁), ethyl (C₂), n-propyl(C₃), isopropyl (C₃), n-butyl (C₄), tert-butyl (C₄), sec-butyl (C₄),iso-butyl (C₄), n-pentyl (C₅), 3-pentanyl (C₅), amyl (C₅), neopentyl(C₅), 3-methyl-2-butanyl (C₅), tertiary amyl (C₅), and n-hexyl (C₆).Additional examples of alkyl groups include n-heptyl (C₇), n-octyl (C₈)and the like. Unless otherwise specified, each instance of an alkylgroup is independently unsubstituted (an “unsubstituted alkyl”) orsubstituted (a “substituted alkyl”) with one or more substituents. Incertain embodiments, the alkyl group is an unsubstituted C₁₋₁₀ alkyl(e.g., —CH₃). In certain embodiments, the alkyl group is a substitutedC₁₋₁₀ alkyl.

The term “haloalkyl” is a substituted alkyl group, wherein one or moreof the hydrogen atoms are independently replaced by a halogen, e.g.,fluoro, bromo, chloro, or iodo. “Perhaloalkyl” is a subset of haloalkyl,and refers to an alkyl group wherein all of the hydrogen atoms areindependently replaced by a halogen, e.g., fluoro, bromo, chloro, oriodo. In some embodiments, the haloalkyl moiety has 1 to 8 carbon atoms(“C₁₋₈ haloalkyl”). In some embodiments, the haloalkyl moiety has 1 to 6carbon atoms (“C₁₋₆ haloalkyl”). In some embodiments, the haloalkylmoiety has 1 to 4 carbon atoms (“C₁₋₄ haloalkyl”). In some embodiments,the haloalkyl moiety has 1 to 3 carbon atoms (“C₁₋₃ haloalkyl”). In someembodiments, the haloalkyl moiety has 1 to 2 carbon atoms (“C₁₋₂haloalkyl”). In some embodiments, all of the haloalkyl hydrogen atomsare replaced with fluoro to provide a perfluoroalkyl group. In someembodiments, all of the haloalkyl hydrogen atoms are replaced withchloro to provide a “perchloroalkyl” group. Examples of haloalkyl groupsinclude —CF₃, —CF₂CF₃, —CF₂CF₂CF₃, —CCl₃, —CFCl₂, —CF₂Cl, and the like.

The term “heteroalkyl” refers to an alkyl group, which further includesat least one heteroatom (e.g., 1, 2, 3, or 4 heteroatoms) selected fromoxygen, nitrogen, or sulfur within (i.e., inserted between adjacentcarbon atoms of) and/or placed at one or more terminal position(s) ofthe parent chain. In certain embodiments, a heteroalkyl group refers toa saturated group having from 1 to 10 carbon atoms and 1 or moreheteroatoms within the parent chain (“heteroC₁₋₁₀ alkyl”). In someembodiments, a heteroalkyl group is a saturated group having 1 to 9carbon atoms and 1 or more heteroatoms within the parent chain(“heteroC₁₋₉ alkyl”). In some embodiments, a heteroalkyl group is asaturated group having 1 to 8 carbon atoms and 1 or more heteroatomswithin the parent chain (“heteroC₁ ₈ alkyl”). In some embodiments, aheteroalkyl group is a saturated group having 1 to 7 carbon atoms and 1or more heteroatoms within the parent chain (“heteroC₁₋₇ alkyl”). Insome embodiments, a heteroalkyl group is a saturated group having 1 to 6carbon atoms and 1 or more heteroatoms within the parent chain(“heteroC₁₋₆ alkyl”). In some embodiments, a heteroalkyl group is asaturated group having 1 to 5 carbon atoms and 1 or 2 heteroatoms withinthe parent chain (“heteroC₁₋₅ alkyl”). In some embodiments, aheteroalkyl group is a saturated group having 1 to 4 carbon atoms andfor 2 heteroatoms within the parent chain (“heteroC₁₋₄ alkyl”). In someembodiments, a heteroalkyl group is a saturated group having 1 to 3carbon atoms and 1 heteroatom within the parent chain (“heteroC₁₋₃alkyl”). In some embodiments, a heteroalkyl group is a saturated grouphaving 1 to 2 carbon atoms and 1 heteroatom within the parent chain(“heteroC₁₋₂ alkyl”). In some embodiments, a heteroalkyl group is asaturated group having 1 carbon atom and 1 heteroatom (“heteroC₁alkyl”). In some embodiments, a heteroalkyl group is a saturated grouphaving 2 to 6 carbon atoms and 1 or 2 heteroatoms within the parentchain (“heteroC₂₋₆ alkyl”). Unless otherwise specified, each instance ofa heteroalkyl group is independently unsubstituted (an “unsubstitutedheteroalkyl”) or substituted (a “substituted heteroalkyl”) with one ormore substituents. In certain embodiments, the heteroalkyl group is anunsubstituted heteroC₁₋₁₀ alkyl. In certain embodiments, the heteroalkylgroup is a substituted heteroC₁₋₁₀ alkyl.

The term “alkenyl” refers to a radical of a straight-chain or branchedhydrocarbon group having from 2 to 10 carbon atoms and one or morecarbon-carbon double bonds (e.g., 1, 2, 3, or 4 double bonds). In someembodiments, an alkenyl group has 2 to 9 carbon atoms (“C₂₋₉ alkenyl”).In some embodiments, an alkenyl group has 2 to 8 carbon atoms (“C₂₋₈alkenyl”). In some embodiments, an alkenyl group has 2 to 7 carbon atoms(“C₂₋₇ alkenyl”). In some embodiments, an alkenyl group has 2 to 6carbon atoms (“C₂₋₆ alkenyl”). In some embodiments, an alkenyl group has2 to 5 carbon atoms (“C₂₋₅ alkenyl”). In some embodiments, an alkenylgroup has 2 to 4 carbon atoms (“C₂₋₄ alkenyl”). In some embodiments, analkenyl group has 2 to 3 carbon atoms (“C₂ ₃ alkenyl”). In someembodiments, an alkenyl group has 2 carbon atoms (“C₂ alkenyl”). The oneor more carbon-carbon double bonds can be internal (such as in2-butenyl) or terminal (such as in 1-butenyl). Examples of C₂₋₄ alkenylgroups include ethenyl (C₂), 1-propenyl (C₃), 2-propenyl (C₃), 1-butenyl(C₄), 2-butenyl (C₄), butadienyl (C₄), and the like. Examples of C₂₋₆alkenyl groups include the aforementioned C₂₋₄ alkenyl groups as well aspentenyl (C₅), pentadienyl (C₅), hexenyl (C₆), and the like. Additionalexamples of alkenyl include heptenyl (C₇), octenyl (C₈), octatrienyl(C₈), and the like. Unless otherwise specified, each instance of analkenyl group is independently unsubstituted (an “unsubstitutedalkenyl”) or substituted (a “substituted alkenyl”) with one or moresubstituents. In certain embodiments, the alkenyl group is anunsubstituted C₂₋₁₀ alkenyl. In certain embodiments, the alkenyl groupis a substituted C₂₋₁₀ alkenyl. In an alkenyl group, a C═C double bondfor which the stereochemistry is unspecified

may be an (E)- or (4-double bond.

The term “heteroalkenyl” refers to an alkenyl group, which furtherincludes at least one heteroatom (e.g., 1, 2, 3, or 4 heteroatoms)selected from oxygen, nitrogen, or sulfur within (i.e., inserted betweenadjacent carbon atoms of) and/or placed at one or more terminalposition(s) of the parent chain. In certain embodiments, a heteroalkenylgroup refers to a group having from 2 to 10 carbon atoms, at least onedouble bond, and 1 or more heteroatoms within the parent chain(“heteroC₂₋₁₀ alkenyl”). In some embodiments, a heteroalkenyl group has2 to 9 carbon atoms at least one double bond, and 1 or more heteroatomswithin the parent chain (“heteroC₂₋₉ alkenyl”). In some embodiments, aheteroalkenyl group has 2 to 8 carbon atoms, at least one double bond,and 1 or more heteroatoms within the parent chain (“heteroC₂₋₈alkenyl”). In some embodiments, a heteroalkenyl group has 2 to 7 carbonatoms, at least one double bond, and 1 or more heteroatoms within theparent chain (“heteroC₂₋₇ alkenyl”). In some embodiments, aheteroalkenyl group has 2 to 6 carbon atoms, at least one double bond,and 1 or more heteroatoms within the parent chain (“heteroC₂₋₆alkenyl”). In some embodiments, a heteroalkenyl group has 2 to 5 carbonatoms, at least one double bond, and 1 or 2 heteroatoms within theparent chain (“heteroC₂₋₅ alkenyl”). In some embodiments, aheteroalkenyl group has 2 to 4 carbon atoms, at least one double bond,and for 2 heteroatoms within the parent chain (“heteroC₂ ₄ alkenyl”). Insome embodiments, a heteroalkenyl group has 2 to 3 carbon atoms, atleast one double bond, and 1 heteroatom within the parent chain(“heteroC₂₋₃ alkenyl”). In some embodiments, a heteroalkenyl group has 2to 6 carbon atoms, at least one double bond, and 1 or 2 heteroatomswithin the parent chain (“heteroC₂₋₆ alkenyl”). Unless otherwisespecified, each instance of a heteroalkenyl group is independentlyunsubstituted (an “unsubstituted heteroalkenyl”) or substituted (a“substituted heteroalkenyl”) with one or more substituents. In certainembodiments, the heteroalkenyl group is an unsubstituted heteroC₂₋₁₀alkenyl. In certain embodiments, the heteroalkenyl group is asubstituted heteroC₂₋₁₀ alkenyl.

The term “alkynyl” refers to a radical of a straight-chain or branchedhydrocarbon group having from 2 to 10 carbon atoms and one or morecarbon-carbon triple bonds (e.g., 1, 2, 3, or 4 triple bonds) (“C₂₋₁₀alkynyl”). In some embodiments, an alkynyl group has 2 to 9 carbon atoms(“C₂₋₉ alkynyl”). In some embodiments, an alkynyl group has 2 to 8carbon atoms (“C₂₋₈ alkynyl”). In some embodiments, an alkynyl group has2 to 7 carbon atoms (“C₂₋₇ alkynyl”). In some embodiments, an alkynylgroup has 2 to 6 carbon atoms (“C₂₋₆ alkynyl”). In some embodiments, analkynyl group has 2 to 5 carbon atoms (“C₂ ₅ alkynyl”). In someembodiments, an alkynyl group has 2 to 4 carbon atoms (“C₂₋₄ alkynyl”).In some embodiments, an alkynyl group has 2 to 3 carbon atoms (“C₂₋₃alkynyl”). In some embodiments, an alkynyl group has 2 carbon atoms (“C₂alkynyl”). The one or more carbon-carbon triple bonds can be internal(such as in 2-butynyl) or terminal (such as in 1-butynyl). Examples ofC₂ ₄ alkynyl groups include, without limitation, ethynyl (C₂),1-propynyl (C₃), 2-propynyl (C₃), 1-butynyl (C₄), 2-butynyl (C₄), andthe like. Examples of C₂₋₆ alkenyl groups include the aforementionedC₂₋₄ alkynyl groups as well as pentynyl (C₅), hexynyl (C₆), and thelike. Additional examples of alkynyl include heptynyl (C₇), octynyl(C₈), and the like. Unless otherwise specified, each instance of analkynyl group is independently unsubstituted (an “unsubstitutedalkynyl”) or substituted (a “substituted alkynyl”) with one or moresubstituents. In certain embodiments, the alkynyl group is anunsubstituted C₂₋₁₀ alkynyl. In certain embodiments, the alkynyl groupis a substituted C₂₋₁₀ alkynyl.

The term “heteroalkynyl” refers to an alkynyl group, which furtherincludes at least one heteroatom (e.g., 1, 2, 3, or 4 heteroatoms)selected from oxygen, nitrogen, or sulfur within (i.e., inserted betweenadjacent carbon atoms of) and/or placed at one or more terminalposition(s) of the parent chain. In certain embodiments, a heteroalkynylgroup refers to a group having from 2 to 10 carbon atoms, at least onetriple bond, and 1 or more heteroatoms within the parent chain(“heteroC₂₋₁₀ alkynyl”). In some embodiments, a heteroalkynyl group has2 to 9 carbon atoms, at least one triple bond, and 1 or more heteroatomswithin the parent chain (“heteroC₂₋₉ alkynyl”). In some embodiments, aheteroalkynyl group has 2 to 8 carbon atoms, at least one triple bond,and 1 or more heteroatoms within the parent chain (“heteroC₂₋₈alkynyl”). In some embodiments, a heteroalkynyl group has 2 to 7 carbonatoms, at least one triple bond, and 1 or more heteroatoms within theparent chain (“heteroC₂₋₇ alkynyl”). In some embodiments, aheteroalkynyl group has 2 to 6 carbon atoms, at least one triple bond,and 1 or more heteroatoms within the parent chain (“heteroC₂₋₆alkynyl”). In some embodiments, a heteroalkynyl group has 2 to 5 carbonatoms, at least one triple bond, and 1 or 2 heteroatoms within theparent chain (“heteroC₂₋₅ alkynyl”). In some embodiments, aheteroalkynyl group has 2 to 4 carbon atoms, at least one triple bond,and for 2 heteroatoms within the parent chain (“heteroC₂ ₄ alkynyl”). Insome embodiments, a heteroalkynyl group has 2 to 3 carbon atoms, atleast one triple bond, and 1 heteroatom within the parent chain(“heteroC₂₋₃ alkynyl”). In some embodiments, a heteroalkynyl group has 2to 6 carbon atoms, at least one triple bond, and 1 or 2 heteroatomswithin the parent chain (“heteroC₂₋₆ alkynyl”). Unless otherwisespecified, each instance of a heteroalkynyl group is independentlyunsubstituted (an “unsubstituted heteroalkynyl”) or substituted (a“substituted heteroalkynyl”) with one or more substituents. In certainembodiments, the heteroalkynyl group is an unsubstituted heteroC₂₋₁₀alkynyl. In certain embodiments, the heteroalkynyl group is asubstituted heteroC₂₋₁₀ alkynyl.

The term “carbocyclyl” or “carbocyclic” refers to a radical of anon-aromatic cyclic hydrocarbon group having from 3 to 14 ring carbonatoms (“C₃ ₁₄ carbocyclyl”) and zero heteroatoms in the non-aromaticring system. In some embodiments, a carbocyclyl group has 3 to 10 ringcarbon atoms (“C₃₋₁₀ carbocyclyl”). In some embodiments, a carbocyclylgroup has 3 to 8 ring carbon atoms (“C₃₋₈ carbocyclyl”). In someembodiments, a carbocyclyl group has 3 to 7 ring carbon atoms (“C₃₋₇carbocyclyl”). In some embodiments, a carbocyclyl group has 3 to 6 ringcarbon atoms (“C₃₋₆ carbocyclyl”). In some embodiments, a carbocyclylgroup has 4 to 6 ring carbon atoms (“C₄₋₆ carbocyclyl”). In someembodiments, a carbocyclyl group has 5 to 6 ring carbon atoms (“C₅₋₆carbocyclyl”). In some embodiments, a carbocyclyl group has 5 to 10 ringcarbon atoms (“C₅₋₁₀ carbocyclyl”). Exemplary C₃₋₆ carbocyclyl groupsinclude, without limitation, cyclopropyl (C₃), cyclopropenyl (C₃),cyclobutyl (C₄), cyclobutenyl (C₄), cyclopentyl (C₅), cyclopentenyl(C₅), cyclohexyl (C₆), cyclohexenyl (C₆), cyclohexadienyl (C₆), and thelike. Exemplary C₃₋₈ carbocyclyl groups include, without limitation, theaforementioned C₃₋₆ carbocyclyl groups as well as cycloheptyl (C₇),cycloheptenyl (C₇), cycloheptadienyl (C₇), cycloheptatrienyl (C₇),cyclooctyl (C₈), cyclooctenyl (C₈), bicyclo[2.2.1]heptanyl (C₇),bicyclo[2.2.2]octanyl (C₈), and the like. Exemplary C₃₋₁₀ carbocyclylgroups include, without limitation, the aforementioned C₃₋₈ carbocyclylgroups as well as cyclononyl (C₉), cyclononenyl (C₉), cyclodecyl (C₁₀),cyclodecenyl (C₁₀), octahydro-1H-indenyl (C₉), decahydronaphthalenyl(C₁₀), spiro[4.5]decanyl (C₁₀), and the like. As the foregoing examplesillustrate, in certain embodiments, the carbocyclyl group is eithermonocyclic (“monocyclic carbocyclyl”) or polycyclic (e.g., containing afused, bridged or spiro ring system such as a bicyclic system (“bicycliccarbocyclyl”) or tricyclic system (“tricyclic carbocyclyl”)) and can besaturated or can contain one or more carbon-carbon double or triplebonds. “Carbocyclyl” also includes ring systems wherein the carbocyclylring, as defined above, is fused with one or more aryl or heteroarylgroups wherein the point of attachment is on the carbocyclyl ring, andin such instances, the number of carbons continue to designate thenumber of carbons in the carbocyclic ring system. Unless otherwisespecified, each instance of a carbocyclyl group is independentlyunsubstituted (an “unsubstituted carbocyclyl”) or substituted (a“substituted carbocyclyl”) with one or more substituents. In certainembodiments, the carbocyclyl group is an unsubstituted C₃ ₁₄carbocyclyl. In certain embodiments, the carbocyclyl group is asubstituted C₃₋₁₄ carbocyclyl.

In some embodiments, “carbocyclyl” is a monocyclic, saturatedcarbocyclyl group having from 3 to 14 ring carbon atoms (“C₃₋₁₄cycloalkyl”). In some embodiments, a cycloalkyl group has 3 to 10 ringcarbon atoms (“C₃₋₁₀ cycloalkyl”). In some embodiments, a cycloalkylgroup has 3 to 8 ring carbon atoms (“C₃₋₈ cycloalkyl”). In someembodiments, a cycloalkyl group has 3 to 6 ring carbon atoms (“C₃₋₆cycloalkyl”). In some embodiments, a cycloalkyl group has 4 to 6 ringcarbon atoms (“C₄₋₆ cycloalkyl”). In some embodiments, a cycloalkylgroup has 5 to 6 ring carbon atoms (“C₅₋₆ cycloalkyl”). In someembodiments, a cycloalkyl group has 5 to 10 ring carbon atoms (“C₅₋₁₀cycloalkyl”). Examples of C₅₋₆ cycloalkyl groups include cyclopentyl(C₅) and cyclohexyl (C₅). Examples of C₃₋₆ cycloalkyl groups include theaforementioned C₅₋₆ cycloalkyl groups as well as cyclopropyl (C₃) andcyclobutyl (C₄). Examples of C₃₋₈ cycloalkyl groups include theaforementioned C₃₋₆ cycloalkyl groups as well as cycloheptyl (C₇) andcyclooctyl (C₈). Unless otherwise specified, each instance of acycloalkyl group is independently unsubstituted (an “unsubstitutedcycloalkyl”) or substituted (a “substituted cycloalkyl”) with one ormore substituents. In certain embodiments, the cycloalkyl group is anunsubstituted C₃₋₁₄ cycloalkyl. In certain embodiments, the cycloalkylgroup is a substituted C₃₋₁₄ cycloalkyl.

The term “heterocyclyl” or “heterocyclic” refers to a radical of a 3- to14-membered non-aromatic ring system having ring carbon atoms and 1 to 4ring heteroatoms, wherein each heteroatom is independently selected fromnitrogen, oxygen, and sulfur (“3-14 membered heterocyclyl”). Inheterocyclyl groups that contain one or more nitrogen atoms, the pointof attachment can be a carbon or nitrogen atom, as valency permits. Aheterocyclyl group can either be monocyclic (“monocyclic heterocyclyl”)or polycyclic (e.g., a fused, bridged or spiro ring system such as abicyclic system (“bicyclic heterocyclyl”) or tricyclic system(“tricyclic heterocyclyl”)), and can be saturated or can contain one ormore carbon-carbon double or triple bonds. Heterocyclyl polycyclic ringsystems can include one or more heteroatoms in one or both rings.“Heterocyclyl” also includes ring systems wherein the heterocyclyl ring,as defined above, is fused with one or more carbocyclyl groups whereinthe point of attachment is either on the carbocyclyl or heterocyclylring, or ring systems wherein the heterocyclyl ring, as defined above,is fused with one or more aryl or heteroaryl groups, wherein the pointof attachment is on the heterocyclyl ring, and in such instances, thenumber of ring members continue to designate the number of ring membersin the heterocyclyl ring system. Unless otherwise specified, eachinstance of heterocyclyl is independently unsubstituted (an“unsubstituted heterocyclyl”) or substituted (a “substitutedheterocyclyl”) with one or more substituents. In certain embodiments,the heterocyclyl group is an unsubstituted 3-14 membered heterocyclyl.In certain embodiments, the heterocyclyl group is a substituted 3-14membered heterocyclyl.

In some embodiments, a heterocyclyl group is a 5-10 memberednon-aromatic ring system having ring carbon atoms and 1-4 ringheteroatoms, wherein each heteroatom is independently selected fromnitrogen, oxygen, and sulfur (“5-10 membered heterocyclyl”). In someembodiments, a heterocyclyl group is a 5-8 membered non-aromatic ringsystem having ring carbon atoms and 1-4 ring heteroatoms, wherein eachheteroatom is independently selected from nitrogen, oxygen, and sulfur(“5-8 membered heterocyclyl”). In some embodiments, a heterocyclyl groupis a 5-6 membered non-aromatic ring system having ring carbon atoms and1-4 ring heteroatoms, wherein each heteroatom is independently selectedfrom nitrogen, oxygen, and sulfur (“5-6 membered heterocyclyl”). In someembodiments, the 5-6 membered heterocyclyl has 1-3 ring heteroatomsselected from nitrogen, oxygen, and sulfur. In some embodiments, the 5-6membered heterocyclyl has 1-2 ring heteroatoms selected from nitrogen,oxygen, and sulfur. In some embodiments, the 5-6 membered heterocyclylhas 1 ring heteroatom selected from nitrogen, oxygen, and sulfur.

Exemplary 3-membered heterocyclyl groups containing 1 heteroatominclude, without limitation, azirdinyl, oxiranyl, and thiiranyl.Exemplary 4-membered heterocyclyl groups containing 1 heteroatominclude, without limitation, azetidinyl, oxetanyl, and thietanyl.Exemplary 5-membered heterocyclyl groups containing 1 heteroatominclude, without limitation, tetrahydrofuranyl, dihydrofuranyl,tetrahydrothiophenyl, dihydrothiophenyl, pyrrolidinyl, dihydropyrrolyl,and pyrrolyl-2,5-dione. Exemplary 5-membered heterocyclyl groupscontaining 2 heteroatoms include, without limitation, dioxolanyl,oxathiolanyl and dithiolanyl. Exemplary 5-membered heterocyclyl groupscontaining 3 heteroatoms include, without limitation, triazolinyl,oxadiazolinyl, and thiadiazolinyl. Exemplary 6-membered heterocyclylgroups containing 1 heteroatom include, without limitation, piperidinyl,tetrahydropyranyl, dihydropyridinyl, and thianyl. Exemplary 6-memberedheterocyclyl groups containing 2 heteroatoms include, withoutlimitation, piperazinyl, morpholinyl, dithianyl, and dioxanyl. Exemplary6-membered heterocyclyl groups containing 2 heteroatoms include, withoutlimitation, triazinanyl. Exemplary 7-membered heterocyclyl groupscontaining 1 heteroatom include, without limitation, azepanyl, oxepanyland thiepanyl. Exemplary 8-membered heterocyclyl groups containing 1heteroatom include, without limitation, azocanyl, oxecanyl andthiocanyl. Exemplary bicyclic heterocyclyl groups include, withoutlimitation, indolinyl, isoindolinyl, dihydrobenzofuranyl,dihydrobenzothienyl, tetrahydrobenzothienyl, tetrahydrobenzofuranyl,tetrahydroindolyl, tetrahydroquinolinyl, tetrahydroisoquinolinyl,decahydroquinolinyl, decahydroisoquinolinyl, octahydrochromenyl,octahydroisochromenyl, decahydronaphthyridinyl,decahydro-1,8-naphthyridinyl, octahydropyrrolo[3,2-b]pyrrole, indolinyl,phthalimidyl, naphthalimidyl, chromanyl, chromenyl,1H-benzo[e][1,4]diazepinyl, 1,4,5,7-tetrahydropyrano[3,4-b]pyrrolyl,5,6-dihydro-4H-furo[3,2-b]pyrrolyl, 6,7-dihydro-5H-furo[3,2-b]pyranyl,5,7-dihydro-4H-thieno[2,3-c]pyranyl,2,3-dihydro-1H-pyrrolo[2,3-b]pyridinyl, 2,3-dihydrofuro[2,3-b]pyridinyl,4,5,6,7-tetrahydro-1H-pyrrolo[2,3-b]pyridinyl,4,5,6,7-tetra-hydrofuro[3,2-c]pyridinyl,4,5,6,7-tetrahydrothieno[3,2-b]pyridinyl,1,2,3,4-tetrahydro-1,6-naphthyridinyl, and the like.

The term “aryl” refers to a radical of a monocyclic or polycyclic (e.g.,bicyclic or tricyclic) 4n+2 aromatic ring system (e.g., having 6, 10, or14 π electrons shared in a cyclic array) having 6-14 ring carbon atomsand zero heteroatoms provided in the aromatic ring system (“C₆₋₁₄aryl”). In some embodiments, an aryl group has 6 ring carbon atoms (“C₆aryl”; e.g., phenyl). In some embodiments, an aryl group has 10 ringcarbon atoms (“C₁₀ aryl”; e.g., naphthyl such as 1-naphthyl and2-naphthyl). In some embodiments, an aryl group has 14 ring carbon atoms(“C₁₄ aryl”; e.g., anthracyl). “Aryl” also includes ring systems whereinthe aryl ring, as defined above, is fused with one or more carbocyclylor heterocyclyl groups wherein the radical or point of attachment is onthe aryl ring, and in such instances, the number of carbon atomscontinue to designate the number of carbon atoms in the aryl ringsystem. Unless otherwise specified, each instance of an aryl group isindependently unsubstituted (an “unsubstituted aryl”) or substituted (a“substituted aryl”) with one or more substituents. In certainembodiments, the aryl group is an unsubstituted C₆₋₁₄ aryl. In certainembodiments, the aryl group is a substituted C₆₋₁₄ aryl.

“Aralkyl” is a subset of “alkyl” and refers to an alkyl groupsubstituted by an aryl group, wherein the point of attachment is on thealkyl moiety.

The term “heteroaryl” refers to a radical of a 5-14 membered monocyclicor polycyclic (e.g., bicyclic, tricyclic) 4n+2 aromatic ring system(e.g., having 6,10, or 14 π electrons shared in a cyclic array) havingring carbon atoms and 1-4 ring heteroatoms provided in the aromatic ringsystem, wherein each heteroatom is independently selected from nitrogen,oxygen, and sulfur (“5-14 membered heteroaryl”). In heteroaryl groupsthat contain one or more nitrogen atoms, the point of attachment can bea carbon or nitrogen atom, as valency permits. Heteroaryl polycyclicring systems can include one or more heteroatoms in one or both rings.“Heteroaryl” includes ring systems wherein the heteroaryl ring, asdefined above, is fused with one or more carbocyclyl or heterocyclylgroups wherein the point of attachment is on the heteroaryl ring, and insuch instances, the number of ring members continue to designate thenumber of ring members in the heteroaryl ring system. “Heteroaryl” alsoincludes ring systems wherein the heteroaryl ring, as defined above, isfused with one or more aryl groups wherein the point of attachment iseither on the aryl or heteroaryl ring, and in such instances, the numberof ring members designates the number of ring members in the fusedpolycyclic (aryl/heteroaryl) ring system. Polycyclic heteroaryl groupswherein one ring does not contain a heteroatom (e.g., indolyl,quinolinyl, carbazolyl, and the like) the point of attachment can be oneither ring, i.e., either the ring bearing a heteroatom (e.g.,2-indolyl) or the ring that does not contain a heteroatom (e.g.,5-indolyl).

In some embodiments, a heteroaryl group is a 5-10 membered aromatic ringsystem having ring carbon atoms and 1-4 ring heteroatoms provided in thearomatic ring system, wherein each heteroatom is independently selectedfrom nitrogen, oxygen, and sulfur (“5-10 membered heteroaryl”). In someembodiments, a heteroaryl group is a 5-8 membered aromatic ring systemhaving ring carbon atoms and 1-4 ring heteroatoms provided in thearomatic ring system, wherein each heteroatom is independently selectedfrom nitrogen, oxygen, and sulfur (“5-8 membered heteroaryl”). In someembodiments, a heteroaryl group is a 5-6 membered aromatic ring systemhaving ring carbon atoms and 1-4 ring heteroatoms provided in thearomatic ring system, wherein each heteroatom is independently selectedfrom nitrogen, oxygen, and sulfur (“5-6 membered heteroaryl”). In someembodiments, the 5-6 membered heteroaryl has 1-3 ring heteroatomsselected from nitrogen, oxygen, and sulfur. In some embodiments, the 5-6membered heteroaryl has 1-2 ring heteroatoms selected from nitrogen,oxygen, and sulfur. In some embodiments, the 5-6 membered heteroaryl has1 ring heteroatom selected from nitrogen, oxygen, and sulfur. Unlessotherwise specified, each instance of a heteroaryl group isindependently unsubstituted (an “unsubstituted heteroaryl”) orsubstituted (a “substituted heteroaryl”) with one or more substituents.In certain embodiments, the heteroaryl group is an unsubstituted 5-14membered heteroaryl. In certain embodiments, the heteroaryl group is asubstituted 5-14 membered heteroaryl.

Exemplary 5-membered heteroaryl groups containing 1 heteroatom include,without limitation, pyrrolyl, furanyl, and thiophenyl. Exemplary5-membered heteroaryl groups containing 2 heteroatoms include, withoutlimitation, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, thiazolyl, andisothiazolyl. Exemplary 5-membered heteroaryl groups containing 3heteroatoms include, without limitation, triazolyl, oxadiazolyl, andthiadiazolyl. Exemplary 5-membered heteroaryl groups containing 4heteroatoms include, without limitation, tetrazolyl. Exemplary6-membered heteroaryl groups containing 1 heteroatom include, withoutlimitation, pyridinyl. Exemplary 6-membered heteroaryl groups containing2 heteroatoms include, without limitation, pyridazinyl, pyrimidinyl, andpyrazinyl. Exemplary 6-membered heteroaryl groups containing 3 or 4heteroatoms include, without limitation, triazinyl and tetrazinyl,respectively. Exemplary 7-membered heteroaryl groups containing 1heteroatom include, without limitation, azepinyl, oxepinyl, andthiepinyl. Exemplary 5,6-bicyclic heteroaryl groups include, withoutlimitation, indolyl, isoindolyl, indazolyl, benzotriazolyl,benzothiophenyl, isobenzothiophenyl, benzofuranyl, benzoisofuranyl,benzimidazolyl, benzoxazolyl, benzisoxazolyl, benzoxadiazolyl,benzthiazolyl, benzisothiazolyl, benzthiadiazolyl, indolizinyl, andpurinyl. Exemplary 6,6-bicyclic heteroaryl groups include, withoutlimitation, naphthyridinyl, pteridinyl, quinolinyl, isoquinolinyl,cinnolinyl, quinoxalinyl, phthalazinyl, and quinazolinyl. Exemplarytricyclic heteroaryl groups include, without limitation,phenanthridinyl, dibenzofuranyl, carbazolyl, acridinyl, phenothiazinyl,phenoxazinyl and phenazinyl.

“Heteroaralkyl” is a subset of “alkyl” and refers to an alkyl groupsubstituted by a heteroaryl group, wherein the point of attachment is onthe alkyl moiety.

The term “unsaturated bond” refers to a double or triple bond.

The term “unsaturated” or “partially unsaturated” refers to a moietythat includes at least one double or triple bond.

The term “saturated” refers to a moiety that does not contain a doubleor triple bond, i.e., the moiety only contains single bonds.

Affixing the suffix “-ene” to a group indicates the group is a divalentmoiety, e.g., alkylene is the divalent moiety of alkyl, alkenylene isthe divalent moiety of alkenyl, alkynylene is the divalent moiety ofalkynyl, heteroalkylene is the divalent moiety of heteroalkyl,heteroalkenylene is the divalent moiety of heteroalkenyl,heteroalkynylene is the divalent moiety of heteroalkynyl, carbocyclyleneis the divalent moiety of carbocyclyl, heterocyclylene is the divalentmoiety of heterocyclyl, arylene is the divalent moiety of aryl, andheteroarylene is the divalent moiety of heteroaryl.

A group is optionally substituted unless expressly provided otherwise.In certain embodiments, alkyl, alkenyl, alkynyl, heteroalkyl,heteroalkenyl, heteroalkynyl, carbocyclyl, heterocyclyl, aryl, andheteroaryl groups are optionally substituted. “Optionally substituted”refers to a group which may be substituted or unsubstituted (e.g.,“substituted” or “unsubstituted” alkyl, “substituted” or “unsubstituted”alkenyl, “substituted” or “unsubstituted” alkynyl, “substituted” or“unsubstituted” heteroalkyl, “substituted” or “unsubstituted”heteroalkenyl, “substituted” or “unsubstituted” heteroalkynyl,“substituted” or “unsubstituted” carbocyclyl, “substituted” or“unsubstituted” heterocyclyl, “substituted” or “unsubstituted” aryl or“substituted” or “unsubstituted” heteroaryl group). In general, the term“substituted” means that at least one hydrogen present on a group isreplaced with a permissible substituent, e.g., a substituent which uponsubstitution results in a stable compound, e.g., a compound which doesnot spontaneously undergo transformation such as by rearrangement,cyclization, elimination, or other reaction. Unless otherwise indicated,a “substituted” group has a substituent at one or more substitutablepositions of the group, and when more than one position in any givenstructure is substituted, the substituent is either the same ordifferent at each position. The term “substituted” is contemplated toinclude substitution with all permissible substituents of organiccompounds, and includes any of the substituents described herein thatresults in the formation of a stable compound. The present disclosurecontemplates any and all such combinations in order to arrive at astable compound. For purposes of this disclosure, heteroatoms such asnitrogen may have hydrogen substituents and/or any suitable substituentas described herein which satisfy the valencies of the heteroatoms andresults in the formation of a stable moiety.

Exemplary carbon atom substituents include, but are not limited to,halogen, —CN, —NO₂, —N₃, —SO₂H, —SO₃H, —OH, —OR^(aa), —ON(R^(bb))₂,—N(R^(bb))₂, —N(R^(bb))₃ ⁺X⁻, —N(OR^(cc))R^(bb), —SH, —SR^(aa),—SSR^(cc), —C(═O)R^(aa), —CO₂H, —CHO, —C(OR^(cc))₂, —CO₂R^(aa),—OC(═O)R^(aa), —OCO₂R^(aa), —C(═O)N(R^(bb))₂, —OC(═O)N(R^(bb))₂,—NR^(bb)C(═O)R^(aa), —NR^(bb)CO₂R^(aa), —NR^(bb)C(═O)N(R^(bb))₂,—C(═NR^(bb))R^(aa), —C(═NR^(bb))OR^(aa), —OC(═NR^(bb))R^(aa),—OC(═NR^(bb))OR^(aa), —C(═NR^(bb))N(R^(bb))₂, —OC(═NR^(bb))N(R^(bb))₂,—NR^(bb)C(═NR^(bb))N(R^(bb))₂, —C(═O)NR^(bb)SO₂R^(aa),—NR^(bb)SO₂R^(aa), —SO₂N(R^(bb))₂, —SO₂R^(aa), —SO₂OR^(aa), —OSO₂R^(aa),—S(═O)R^(aa), —OS(═O)R^(aa), —Si(R^(aa))₃,—OSi(R^(aa))₃—C(═S)N(R^(bb))₂, —C(═O)SR^(aa), —C(═S)SR^(aa),—SC(═S)SR^(aa), —SC(═O)SR^(aa), —OC(═O)SR^(aa), —SC(═O)OR^(aa),—SC(═O)R^(aa), —P(═O)₂R^(aa), —OP(═O)₂R^(aa), —P(═O)(R^(aa))₂,—OP(═O)(R^(aa))₂, —OP(═O)(OR^(cc))₂, —P(═O)₂N(R^(bb))₂,—OP(═O)₂N(R^(bb))₂, —P(═O)(NR^(bb))₂, —OP(═O)(NR^(bb))₂,—NR^(bb)P(═O)(OR^(cc))₂, —NR^(bb)P(═O)(NR^(bb))₂, —P(R^(cc))₂,—P(R^(cc))₃, —OP(R^(cc))₂, —OP(R^(cc))₃, —B(R^(aa))₂, —B(OR^(cc))₂,—BR^(aa)(OR^(cc)), C₁₋₁₀ alkyl, C₁₋₁₀ perhaloalkyl, C₂₋₁₀ alkenyl, C₂₋₁₀alkynyl, heteroC₁₋₁₀ alkyl, heteroC₂₋₁₀ alkenyl, heteroC₂₋₁₀ alkynyl,C₃₋₁₀ carbocyclyl, 3-14 membered heterocyclyl, C₆₋₁₄ aryl, and 5-14membered heteroaryl, wherein each alkyl, alkenyl, alkynyl, heteroalkyl,heteroalkenyl, heteroalkynyl, carbocyclyl, heterocyclyl, aryl, andheteroaryl is independently substituted with 0,1,2,3,4, or 5R^(dd)groups;

or two geminal hydrogens on a carbon atom are replaced with the group═O, ═S, ═NN(R^(bb))₂, ═NNR^(bb)C(═O)R^(aa), ═NNR^(bb)C(═O)OR^(aa),═NNR^(bb)S(═O)₂R^(aa), ═NR^(bb), or ═NOR^(cc);

each instance of R^(aa) is, independently, selected from C₁₋₁₀ alkyl,C₁₋₁₀ perhaloalkyl, C₂₋₁₀ alkenyl, C₂₋₁₀ alkynyl, heteroC₁₋₁₀ alkyl,heteroC₂₋₁₀alkenyl, heteroC₂₋₁₀alkynyl, C₃₋₁₀ carbocyclyl, 3-14 memberedheterocyclyl, C₆ ₁₄ aryl, and 5-14 membered heteroaryl, or two R^(aa)groups are joined to form a 3-14 membered heterocyclyl or 5-14 memberedheteroaryl ring, wherein each alkyl, alkenyl, alkynyl, heteroalkyl,heteroalkenyl, heteroalkynyl, carbocyclyl, heterocyclyl, aryl, andheteroaryl is independently substituted with 0,1,2, 3, 4, or 5R^(dd)groups;

each instance of R^(bb) is, independently, selected from hydrogen, —OH,—OR^(aa), —N(R^(cc))₂, —CN, —C(═O)R^(aa), —C(═O)N(R^(cc))₂, —CO₂R^(aa),—SO₂R^(aa), —C(═NR^(cc))OR^(aa), —C(═NR^(cc))N(R^(cc))₂, —SO₂N(R^(cc))₂,—SO₂R^(cc), —SO₂OR^(cc), —SOR^(aa), —C(═S)N(R^(cc))₂, —C(═O)SR^(cc),—C(═S)SR^(cc), —P(═O)₂R^(aa), —P(═O)(R^(aa))₂, —P(═O)₂N(R^(cc))₂,—P(═O)(NR^(cc))₂, C₁₋₁₀ alkyl, C₁₋₁₀ perhaloalkyl, C₂₋₁₀ alkenyl, C₂₋₁₀alkynyl, heteroC₁₋₁₀alkyl, heteroC₂₋₁₀alkenyl, heteroC₂₋₁₀alkynyl, C₃₋₁₀carbocyclyl, 3-14 membered heterocyclyl, C₆₋₁₄ aryl, and 5-14 memberedheteroaryl, or two R^(bb) groups are joined to form a 3-14 memberedheterocyclyl or 5-14 membered heteroaryl ring, wherein each alkyl,alkenyl, alkynyl, heteroalkyl, heteroalkenyl, heteroalkynyl,carbocyclyl, heterocyclyl, aryl, and heteroaryl is independentlysubstituted with 0,1,2,3,4, or 5R^(dd) groups;

each instance of R^(cc) is, independently, selected from hydrogen, C₁₋₁₀alkyl, C₁₋₁₀ perhaloalkyl, C₂₋₁₀ alkenyl, C₂₋₁₀ alkynyl, heteroC₁₋₁₀alkyl, heteroC₂₋₁₀ alkenyl, heteroC₂₋₁₀ alkynyl, C₃ ₁₀ carbocyclyl, 3-14membered heterocyclyl, C₆ ₁₄ aryl, and 5-14 membered heteroaryl, or twoR^(cc) groups are joined to form a 3-14 membered heterocyclyl or 5-14membered heteroaryl ring, wherein each alkyl, alkenyl, alkynyl,heteroalkyl, heteroalkenyl, heteroalkynyl, carbocyclyl, heterocyclyl,aryl, and heteroaryl is independently substituted with 0, 1, 2, 3, 4, or5R^(dd) groups;

each instance of R^(dd) is, independently, selected from halogen, —CN,—NO₂, —N₃, —SO₂H, —SO₃H, —OH, —OR^(ee), —ON(R^(ff))₂, —N(R^(ff))₂,—N(R^(ff))₃ ⁺X⁻, —N(OR^(ee))R^(ff), —SH, —SR^(ee), —SSR^(ee),—C(═O)R^(ee), —CO₂H, —CO₂R^(ee), —OC(═O)R^(ee), —OCO₂R^(ee),—C(═O)N(R^(ff))₂, —OC(═O)N(R^(ff))₂, —NR^(ff)C(═O)R^(ee),—NR^(ff)CO₂R^(ee), —NR^(ff)C(═O)N(R^(ff))₂, —C(═NR^(ff))OR^(ee),—OC(═NR^(ff))R^(ee), —OC(═NR^(ff))OR^(ee), —C(═NR^(ff))N(R^(ff))₂,—OC(═NR^(ff))N(R^(ff))₂, —NR^(ff)C(═NR^(ff))N(R^(ff))₂,—NR^(ff)SO₂R^(ee), —SO₂N(R^(ff))₂, —SO₂R^(ee), —SO₂OR^(ee), —OSO₂R^(ee),—S(═O)R^(ee), —Si(R^(ee))₃, —OSi(R^(ee))₃, —C(═S)N(R^(ff))₂,—C(═O)SR^(ee), —C(═S)SR^(ee), —SC(═S)SR^(ee), —P(═O)₂R^(ee),—P(═O)(R^(ee))₂, —OP(═O)(R^(ee))₂, —OP(═O)(OR^(ee))₂, C₁₋₆ alkyl, C₁₋₆perhaloalkyl, C₂₋₆ alkenyl, C₂₋₆ alkynyl, heteroC₁₋₆alkyl,heteroC₂₋₆alkenyl, heteroC₂₋₆alkynyl, C₃₋₁₀ carbocyclyl, 3-10 memberedheterocyclyl, C₆₋₁₀ aryl, 5-10 membered heteroaryl, wherein each alkyl,alkenyl, alkynyl, heteroalkyl, heteroalkenyl, heteroalkynyl,carbocyclyl, heterocyclyl, aryl, and heteroaryl is independentlysubstituted with 0, 1, 2, 3, 4, or 5 R^(gg) groups, or two geminalR^(dd) substituents can be joined to form ═O or ═S;

each instance of R^(ee) is, independently, selected from C₁₋₆ alkyl,C₁₋₆ perhaloalkyl, C₂₋₆ alkenyl, C₂₋₆ alkynyl, heteroC₁₋₆ alkyl,heteroC₂₋₆alkenyl, heteroC₂₋₆ alkynyl, C₃₋₁₀ carbocyclyl, C₆₋₁₀ aryl,3-10 membered heterocyclyl, and 3-10 membered heteroaryl, wherein eachalkyl, alkenyl, alkynyl, heteroalkyl, heteroalkenyl, heteroalkynyl,carbocyclyl, heterocyclyl, aryl, and heteroaryl is independentlysubstituted with 0, 1, 2, 3, 4, or 5R^(gg) groups;

each instance of R^(ff) is, independently, selected from hydrogen, C₁₋₆alkyl, C₁₋₆ perhaloalkyl, C₂₋₆ alkenyl, C₂₋₆ alkynyl, heteroC₁₋₆alkyl,heteroC₂₋₆alkenyl, heteroC₂₋₆alkynyl, C₃₋₁₀ carbocyclyl, 3-10 memberedheterocyclyl, C₆₋₁₀ aryl and 5-10 membered heteroaryl, or two R^(ff)groups are joined to form a 3-10 membered heterocyclyl or 5-10 memberedheteroaryl ring, wherein each alkyl, alkenyl, alkynyl, heteroalkyl,heteroalkenyl, heteroalkynyl, carbocyclyl, heterocyclyl, aryl, andheteroaryl is independently substituted with 0, 1, 2, 3, 4, or 5R^(gg)groups; and

each instance of R^(gg) is, independently, halogen, —CN, —NO₂, —N₃,—SO₂H, —SO₃H, —OH, —OC₁₋₆ alkyl, —ON(C₁₋₆ alkyl)₂, —N(C₁₋₆ alkyl)₂,—N(C₁₋₆ alkyl)₃ ⁺X⁻, —NH(C₁₋₆ alkyl)₂ ⁺X⁻, —NH₂(C₁ ₆ alkyl) ⁺X⁻, —NH₃⁺X⁻, —N(OC₁ ₆ alkyl)(C₁ ₆ alkyl), —N(OH)(C₁ ₆ alkyl), —NH(OH), —SH,—SC₁₋₆ alkyl, —SS(C₁₋₆ alkyl), —C(═O)(C₁₋₆ alkyl), —CO₂H, —CO₂(C₁₋₆alkyl), —OC(═O)(C₁₋₆ alkyl), —OCO₂(C₁₋₆ alkyl), —C(═O)NH₂, —C(═O)N(C₁₋₆alkyl)₂, —OC(═O)NH(C₁₋₆ alkyl), —NHC(=O)(C₁ alkyl), —N(C₁₋₆alkyl)C(═O)(C₁₋₆ alkyl), —NHCO₂(C₁₋₆ alkyl), —NHC(═O)N(C₁₋₆ alkyl)₂,—NHC(═O)NH(C₁₋₆ alkyl), —NHC(═O)NH₂, —C(═NH)O(C₁₋₆ alkyl),—OC(═NH)(C₁₋₆alkyl), —OC(═NH)OC₁₋₆ alkyl, —C(═NH)N(C₁₋₆ alkyl)₂, -C(═NH)NH(C₁₋₆alkyl), —C(═NH)NH₂, —OC(═NH)N(C₁₋₆ alkyl)₂, —OC(NH)NH(C₁₋₆ alkyl),—OC(NH)NH₂, —NHC(NH)N(C₁ ₆ alkyl)₂, —NHC(═NH)NH₂, —NHSO₂ (C₁₋₆ alkyl),—SO₂N(C₁₋₆ alkyl)₂, —SO₂NH (C₁₋₆ alkyl), —SO₂NH₂, —SO₂C₁ alkyl,—SO₂OC₁₋₆ alkyl, —OSO₂C₁₋₆ alkyl, —SOC₁₋₆ alkyl, —Si(C₁₋₆ alkyl)₃,—OSi(C₁₋₆ alkyl)₃ —C(═S)N(C₁₋₆ alkyl)₂, C(═S)NH(C₁₋₆ alkyl), C(═S)NH₂,—C(═O)S(C₁₋₆ alkyl), —C(═S)SC₁₋₆ alkyl, —SC(═S)SC₁₋₆ alkyl, —P(═O)₂(C₁₋₆alkyl), —P(═O)(C₁₋₆ alkyl)₂, —OP(═O)(C₁₋₆ alkyl)₂, —OP(═O)(OC₁ ₆alkyl)₂, C₁ ₆ alkyl, C₁ ₆ perhaloalkyl, C₂ ₆ alkenyl, C₂ ₆ alkynyl,heteroC₁₋₆alkyl, heteroC₂₋₆alkenyl, heteroC₂₋₆alkynyl, C₃₋₁₀carbocyclyl, C₆₋₁₀ aryl, 3-10 membered heterocyclyl, 5-10 memberedheteroaryl; or two geminal R^(gg) substituents can be joined to form ═Oor ═S; wherein X⁻ is a counterion.

The term “halo” or “halogen” refers to fluorine (fluoro, —F), chlorine(chloro, —Cl), bromine (bromo, —Br), or iodine (iodo, —I).

The term “hydroxyl” or “hydroxy” refers to the group —OH. The term“substituted hydroxyl” or “substituted hydroxyl,” by extension, refersto a hydroxyl group wherein the oxygen atom directly attached to theparent molecule is substituted with a group other than hydrogen, andincludes groups selected from —OR^(aa), —ON(R^(bb))₂, —OC(═O)SR^(aa),—OC(═O)R^(aa), —OCO₂R^(aa), —OC(═O)N(R^(bb))₂, —OC(═NR^(bb))R^(aa),—OC(═NR^(bb))OR^(aa), —OC(═NR^(bb))N(R^(bb))₂, —OS(═O)R^(aa),—OSO₂R^(aa), —OSi(R^(aa))_(3,) —OP(R^(cc))₂, —OP(R^(cc))₃,—OP(═O)₂R^(aa), —OP(═O)(R^(aa))₂, —OP(═O)(OR^(cc))₂, —OP(═O)₂N(R^(bb))₂,and —OP(═O)(NR^(bb))₂, wherein R^(aa), R^(bb), and R^(cc) are as definedherein.

The term “thiol” or “thio” refers to the group —SH. The term“substituted thiol” or “substituted thio,” by extension, refers to athiol group wherein the sulfur atom directly attached to the parentmolecule is substituted with a group other than hydrogen, and includesgroups selected from —SR^(aa), —S═SR^(cc), —SC(═S)SR^(aa),—SC(═O)SR^(aa), —SC(═O)OR^(aa), and —SC(═O)R^(aa), wherein R^(aa) andR^(cc) are as defined herein.

The term “amino” refers to the group —NH₂. The term “substituted amino,”by extension, refers to a monosubstituted amino, a disubstituted amino,or a trisubstituted amino. In certain embodiments, the “substitutedamino” is a monosubstituted amino or a disubstituted amino group.

The term “monosubstituted amino” refers to an amino group wherein thenitrogen atom directly attached to the parent molecule is substitutedwith one hydrogen and one group other than hydrogen, and includes groupsselected from —NH(R^(bb)), —NHC(═O)R^(aa), —NHCO₂R^(aa),—NHC(═O)N(R^(bb))₂, —NHC(═NR^(bb))N(R^(bb))₂, —NHSO₂R^(aa),—NHP(═O)(OR^(cc))₂, and —NHP(═O)(NR^(bb))₂, wherein R^(aa), R^(bb) andR^(cc) are as defined herein, and wherein R^(bb) of the group—NH(R^(bb)) is not hydrogen.

The term “disubstituted amino” refers to an amino group wherein thenitrogen atom directly attached to the parent molecule is substitutedwith two groups other than hydrogen, and includes groups selected from—N(R^(bb))₂, —NR^(bb)C(═O)R^(aa), —NR^(bb)CO₂R^(aa),—NR^(bb)C(═O)N(R^(bb))₂, —NR^(bb)C(═NR^(bb))N(R^(bb))₂,—NR^(bb)SO₂R^(aa), —NR^(bb)P(═O)(OR^(cc))₂, and —NR^(bb)P(═O)(NR^(bb))₂,wherein R^(aa), R^(bb), and R^(cc) are as defined herein, with theproviso that the nitrogen atom directly attached to the parent moleculeis not substituted with hydrogen.

The term “trisubstituted amino” refers to an amino group wherein thenitrogen atom directly attached to the parent molecule is substitutedwith three groups, and includes groups selected from —N(R^(bb))₃ and—N(R^(bb))₃ ⁺X⁻, wherein R^(bb) and X⁻ are as defined herein.

The term “sulfonyl” refers to a group selected from —SO₂N(R^(bb))₂,—SO₂R^(aa), and —SO₂OR^(aa), wherein R^(aa) and R^(bb) are as definedherein.

The term “sulfinyl” refers to the group —S(═O)R^(aa), wherein R^(aa) isas defined herein.

The term “carbonyl” refers a group wherein the carbon directly attachedto the parent molecule is sp² hybridized, and is substituted with anoxygen, nitrogen or sulfur atom, e.g., a group selected from ketones(—C(═O)R^(aa)), carboxylic acids (—CO₂H), aldehydes (—CHO), esters(—CO₂R^(aa), —C(═O)SR^(aa), —C(═S)SR^(aa)), amides (—C(═O)N(R^(bb))₂,—C(═O)NR^(bb)SO₂R^(aa), —C(═S)N(R^(bb))₂), and imines(—C(═NR^(bb))R^(aa), —C(═NR^(bb))OR^(aa)), —C(═NR^(bb))N(R^(bb))₂),wherein R^(aa) and R^(bb) are as defined herein.

The term “silyl” refers to the group —Si(R^(aa))₃, wherein R^(aa) is asdefined herein.

The term “oxo” refers to the group ═O, and the term “thiooxo” refers tothe group ═S.

Nitrogen atoms can be substituted or unsubstituted as valency permits,and include primary, secondary, tertiary, and quaternary nitrogen atoms.Exemplary nitrogen atom substituents include, but are not limited to,hydrogen, —OH, —OR^(aa), —N(R^(cc))₂, —CN, —C(═O)R^(aa),—C(═O)N(R^(cc))₂, —CO₂R^(aa), —SO₂R^(aa), —C(═NR^(bb))R^(aa),—C(═NR^(cc))OR^(aa), —C(═NR^(cc))N(R^(cc))₂, SO₂N(R^(cc))₂, —SO₂R^(cc),—SO₂OR^(cc), —SOR^(aa), —C(═S)N(R^(cc))₂, —C(═O)SR^(cc), —C(═S)SR^(cc),—P(O)₂R^(aa), —P(═O)(R^(aa))₂, —P(═O)₂N(R^(cc))₂, —P(═O)(NR^(cc))₂,C₁₋₁₀ alkyl, C₁₋₁₀ perhaloalkyl, C₂₋₁₀ alkenyl, C₂₋₁₀ alkynyl,heteroC₁₋₁₀alkyl, heteroC₂₋₁₀alkenyl, heteroC₂₋₁₀alkynyl, C₃₋₁₀carbocyclyl, 3-14 membered heterocyclyl, C₆₋₁₄ aryl, and 5-14 memberedheteroaryl, or two R^(cc) groups attached to an N atom are joined toform a 3-14 membered heterocyclyl or 5-14 membered heteroaryl ring,wherein each alkyl, alkenyl, alkynyl, heteroalkyl, heteroalkenyl,heteroalkynyl, carbocyclyl, heterocyclyl, aryl, and heteroaryl isindependently substituted with 0, 1, 2, 3, 4, or 5R^(dd) groups, andwherein R^(aa), R^(bb), R^(cc) and R^(dd) are as defined above.

In certain embodiments, the substituent present on the nitrogen atom isan nitrogen protecting group (also referred to herein as an “aminoprotecting group”). Nitrogen protecting groups include, but are notlimited to, —OH, —OR^(aa), —N(R^(cc))₂, —C(═O)R^(aa), —C(═O)N(R^(cc))₂,—CO₂R^(aa), —SO₂R^(aa), —C(═NR^(cc))R^(aa), —C(═NR^(cc))OR^(aa),—C(═NR^(cc))N(R^(cc))₂, —SO₂N(R^(cc))₂, —SO₂R^(cc), —SO₂OR^(cc),—SOR^(aa), —C(═S)N(R^(cc))₂, —C(═O)SR^(cc), —C(═S)SR^(cc), C₁₋₁₀ alkyl(e.g., aralkyl, heteroaralkyl), C₂₋₁₀ alkenyl, C₂₋₁₀ alkynyl,heteroC₁₋₁₀ alkyl, heteroC₂₋₁₀ alkenyl, heteroC₂₋₁₀ alkynyl, C₃₋₁₀carbocyclyl, 3-14 membered heterocyclyl, C₆₋₁₄ aryl, and 5-14 memberedheteroaryl groups, wherein each alkyl, alkenyl, alkynyl, heteroalkyl,heteroalkenyl, heteroalkynyl, carbocyclyl, heterocyclyl, aralkyl, aryl,and heteroaryl is independently substituted with 0, 1, 2, 3, 4, or5R^(dd) groups, and wherein R^(aa), R^(bb), R^(cc) and R^(dd) are asdefined herein. Nitrogen protecting groups are well known in the art andinclude those described in detail in Protecting Groups in OrganicSynthesis, T. W. Greene and P. G. M. Wuts, 3^(rd) edition, John Wiley &Sons, 1999, incorporated herein by reference.

For example, nitrogen protecting groups such as amide groups (e.g.,—C(═O)R^(aa)) include, but are not limited to, formamide, acetamide,chloroacetamide, trichloroacetamide, trifluoroacetamide,phenylacetamide, 3-phenylpropanamide, picolinamide,3-pyridylcarboxamide, N-benzoylphenylalanyl derivative, benzamide,p-phenylbenzamide, o-nitophenylacetamide, o-nitrophenoxyacetamide,acetoacetamide, (N′-dithiobenzyloxyacylamino)acetamide,3-(p-hydroxyphenyl)propanamide, 3-(o-nitrophenyl)propanamide,2-methyl-2-(o-nitrophenoxy)propanamide,2-methyl-2-(o-phenylazophenoxy)propanamide, 4-chlorobutanamide,3-methyl-3-nitrobutanamide, o-nitrocinnamide, N-acetylmethioninederivative, o-nitrobenzamide and o-(benzoyloxymethyl)benzamide.

Nitrogen protecting groups such as carbamate groups (e.g.,—C(═O)OR^(aa)) include, but are not limited to, methyl carbamate, ethylcarbamante, 9-fluorenylmethyl carbamate (Fmoc),9-(2-sulfo)fluorenylmethyl carbamate, 9-(2,7-dibromo)fluoroenylmethylcarbamate,2,7-di-t-butyl-[9-(10,10-dioxo-10,10,10,10-tetrahydrothioxanthyl)]methylcarbamate (DBD-Tmoc), 4-methoxyphenacyl carbamate (Phenoc),2,2,2-trichloroethyl carbamate (Troc), 2-trimethylsilylethyl carbamate(Teoc), 2-phenylethyl carbamate (hZ), 1-(1-adamantyl)-1-methylethylcarbamate (Adpoc), 1,1-dimethyl-2-haloethyl carbamate,1,1-dimethyl-2,2-dibromoethyl carbamate (DB-t-BOC),1,1-dimethyl-2,2,2-trichloroethyl carbamate (TCBOC),1-methyl-1-(4-biphenylyl)ethyl carbamate (Bpoc),1-(3,5-di-t-butylphenyl)-1-methylethyl carbamate (t-Bumeoc), 2-(2′- and4′-pyridyl)ethyl carbamate (Pyoc), 2-(N,N-dicyclohexylcarboxamido)ethylcarbamate, t-butyl carbamate (BOC or Boc), 1-adamantyl carbamate (Adoc),vinyl carbamate (Voc), allyl carbamate (Alloc), 1-isopropylallylcarbamate (Ipaoc), cinnamyl carbamate (Coc), 4-nitrocinnamyl carbamate(Noc), 8-quinolyl carbamate, N-hydroxypiperidinyl carbamate, alkyldithiocarbamate, benzyl carbamate (Cbz), p-methoxybenzyl carbamate (Moz),p-nitobenzyl carbamate, p-bromobenzyl carbamate, p-chlorobenzylcarbamate, 2,4-dichlorobenzyl carbamate, 4-methylsulfinylbenzylcarbamate (Msz), 9-anthrylmethyl carbamate, diphenylmethyl carbamate,2-methylthioethyl carbamate, 2-methylsulfonylethyl carbamate,2-(p-toluenesulfonyl)ethyl carbamate, [2-(1,3-dithianyl)]methylcarbamate (Dmoc), 4-methylthiophenyl carbamate (Mtpc),2,4-dimethylthiophenyl carbamate (Bmpc), 2-phosphonioethyl carbamate(Peoc), 2-triphenylphosphonioisopropyl carbamate (Ppoc),1,1-dimethyl-2-cyanoethyl carbamate, m-chloro-p-acyloxybenzyl carbamate,p-(dihydroxyboryl)benzyl carbamate, 5-benzisoxazolylmethyl carbamate,2-(trifluoromethyl)-6-chromonylmethyl carbamate (Tcroc), m-nitrophenylcarbamate, 3,5-dimethoxybenzyl carbamate, o-nitrobenzyl carbamate,3,4-dimethoxy-6-nitrobenzyl carbamate, phenyl(o-nitrophenyl)methylcarbamate, t-amyl carbamate, S-benzyl thiocarbamate, p-cyanobenzylcarbamate, cyclobutyl carbamate, cyclohexyl carbamate, cyclopentylcarbamate, cyclopropylmethyl carbamate, p-decyloxybenzyl carbamate,2,2-dimethoxyacylvinyl carbamate, o-(N,N-dimethylcarboxamido)benzylcarbamate, 1,1-dimethyl-3-(N,N-dimethylcarboxamido)propyl carbamate,1,1-dimethylpropynyl carbamate, di(2-pyridyl)methyl carbamate,2-furanylmethyl carbamate, 2-iodoethyl carbamate, isoborynl carbamate,isobutyl carbamate, isonicotinyl carbamate,p-(p′-methoxyphenylazo)benzyl carbamate, 1-methylcyclobutyl carbamate,1-methylcyclohexyl carbamate, 1-methyl-1-cyclopropylmethyl carbamate,1-methyl-1(3,5-dimethoxyphenyl)ethyl carbamate,1-methyl-1-(p-phenylazophenyl)ethyl carbamate, 1-methyl-1-phenylethylcarbamate, 1-methyl-1-(4-pyridyl)ethyl carbamate, phenyl carbamate,p-(phenylazo)benzyl carbamate, 2,4,6-tri-t-butylphenyl carbamate,4-(trimethylammonium)benzyl carbamate, and 2,4,6-trimethylbenzylcarbamate.

Nitrogen protecting groups such as sulfonamide groups (e.g.,—S(═O)₂R^(aa)) include, but are not limited to, p-toluenesulfonamide(Ts), benzenesulfonamide, 2,3,6,-trimethyl-4-methoxybenzenesulfonamide(Mtr), 2,4,6-trimethoxybenzenesulfonamide (Mtb),2,6-dimethyl-4-methoxybenzenesulfonamide (Pme),2,3,5,6-tetramethyl-4-methoxybenzenesulfonamide (Mte),4-methoxybenzenesulfonamide (Mbs), 2,4,6-trimethylbenzenesulfonamide(Mts), 2,6-dimethoxy-4-methylbenzenesulfonamide (iMds),2,2,5,7,8-pentamethylchroman-6-sulfonamide (Pmc), methanesulfonamide(Ms), β-trimethylsilylethanesulfonamide (SES), 9-anthracenesulfonamide,4-(4′,8′-dimethoxynaphthylmethyl)benzenesulfonamide (DNMBS),benzylsulfonamide, trifluoromethylsulfonamide, and phenacylsulfonamide.

Other nitrogen protecting groups include, but are not limited to,phenothiazinyl-(10)-acyl derivative, N′-p-toluenesulfonylaminoacylderivative, N′-phenylaminothioacyl derivative, N-benzoylphenylalanylderivative, N-acetylmethionine derivative,4,5-diphenyl-3-oxazolin-2-one, N-phthalimide, N-dithiasuccinimide (Dts),N-2,3-diphenylmaleimide, N-2,5-dimethylpyrrole,N-1,1,4,4-tetramethyldisilylazacyclopentane adduct (STABASE),5-substituted 1,3-dimethyl-1,3,5-triazacyclohexan-2-one, 5-substituted1,3-dibenzyl-1,3,5-triazacyclohexan-2-one, 1-substituted3,5-dinitro-4-pyridone, N-methylamine, N-allylamine,N-[2-(trimethylsilyl)ethoxy]methylamine (SEM), N-3-acetoxypropylamine,N-(1-isopropyl-4-nitro-2-oxo-3-pyroolin-3-yl)amine, quaternary ammoniumsalts, N-benzylamine, N-di(4-methoxyphenyl)methylamine,N-5-dibenzosuberylamine, N-triphenylmethylamine (Tr),N-[(4-methoxyphenyl)diphenylmethyl] amine (MMTr),N-9-phenylfluorenylamine (PhF),N-2,7-dichloro-9-fluorenylmethyleneamine, N-ferrocenylmethylamino (Fcm),N-2-picolylamino N′-oxide, N-1,1-dimethylthiomethyleneamine,N-benzylideneamine, N-p-methoxybenzylideneamine,N-diphenylmethyleneamine, N-[(2-pyridyl)mesityl]methyleneamine,N-(N′,N′-dimethylaminomethylene)amine, N,N′-isopropylidenediamine,N-p-nitrobenzylideneamine, N-salicylideneamine,N-5-chlorosalicylideneamine,N-(5-chloro-2-hydroxyphenyl)phenylmethyleneamine,N-cyclohexylideneamine, N-(5,5-dimethyl-3-oxo-1-cyclohexenyl)amine,N-borane derivative, N-diphenylborinic acid derivative,N-[phenyl(pentaacylchromium- or tungsten)acyl]amine, N-copper chelate,N-zinc chelate, N-nitroamine, N-nitrosoamine, amine N-oxide,diphenylphosphinamide (Dpp), dimethylthiophosphinamide (Mpt),diphenylthiophosphinamide (Ppt), dialkyl phosphoramidates, dibenzylphosphoramidate, diphenyl phosphoramidate, benzenesulfenamide,o-nitrobenzenesulfenamide (Nps), 2,4-dinitrobenzenesulfenamide,pentachlorobenzenesulfenamide, 2-nitro-4-methoxybenzenesulfenamide,triphenylmethylsulfenamide, and 3-nitropyridinesulfenamide (Npys).

In certain embodiments, the substituent present on an oxygen atom is anoxygen protecting group (also referred to herein as an “hydroxylprotecting group”). Oxygen protecting groups include, but are notlimited to, —R^(aa), —N(R^(bb))₂, —C(═O)SR^(aa), —C(═O)R^(aa),—CO₂R^(aa), —C(═O)N(R^(bb))₂, —C(═NR^(bb))R^(aa), —C(═NR^(bb))OR^(aa),—C(═NR^(bb))N(R^(bb))₂, —S(═O)R^(aa), —SO₂R^(aa), —Si(R^(aa))₃,—P(R^(cc))₂, —P(R^(cc))₃, —P(═O)₂R^(aa), —P(═O)(R^(aa))₂,—P(═O)(OR^(cc))₂, —P(═O)₂N(R^(bb))₂, and —P(═O)(NR^(bb))₂, whereinR^(aa), R^(bb), and R^(cc) are as defined herein. Oxygen protectinggroups are well known in the art and include those described in detailin Protecting Groups in Organic Synthesis, T. W. Greene and P. G. M.Wuts, 3^(rd) edition, John Wiley & Sons, 1999, incorporated herein byreference.

Exemplary oxygen protecting groups include, but are not limited to,methyl, methoxylmethyl (MOM), methylthiomethyl (MTM), t-butylthiomethyl,(phenyldimethylsilyl)methoxymethyl (SMOM), benzyloxymethyl (BOM),p-methoxybenzyloxymethyl (PMBM), (4-methoxyphenoxy)methyl (p-AOM),guaiacolmethyl (GUM), t-butoxymethyl, 4-pentenyloxymethyl (POM),siloxymethyl, 2-methoxyethoxymethyl (MEM), 2,2,2-trichloroethoxymethyl,bis(2-chloroethoxy)methyl, 2-(trimethylsilyl)ethoxymethyl (SEMOR),tetrahydropyranyl (THP), 3-bromotetrahydropyranyl,tetrahydrothiopyranyl, 1-methoxycyclohexyl, 4-methoxytetrahydropyranyl(MTHP), 4-methoxytetrahydrothiopyranyl, 4-methoxytetrahydrothiopyranylS,S-dioxide, 1-[(2-chloro-4-methyl)phenyl]-4-methoxypiperidin-4-yl(CTMP), 1,4-dioxan-2-yl, tetrahydrofuranyl, tetrahydrothiofuranyl,2,3,3a,4,5,6,7,7a-octahydro-7,8,8-trimethyl-4,7-methanobenzofuran-2-yl,1-ethoxyethyl, 1-(2-chloroethoxy)ethyl, 1-methyl-1-methoxyethyl,1-methyl-1-benzyloxyethyl, 1-methyl-1-benzyloxy-2-fluoroethyl,2,2,2-trichloroethyl, 2-trimethylsilylethyl, 2-(phenylselenyl)ethyl,t-butyl, allyl, p-chlorophenyl, p-methoxyphenyl, 2,4-dinitrophenyl,benzyl (Bn), p-methoxybenzyl, 3,4-dimethoxybenzyl, o-nitrobenzyl,p-nitrobenzyl, p-halobenzyl, 2,6-dichlorobenzyl, p-cyanobenzyl,p-phenylbenzyl, 2-picolyl, 4-picolyl, 3-methyl-2-picolylN-oxido,diphenylmethyl, p,p′-dinitrobenzhydryl, 5-dibenzosuberyl,triphenylmethyl, α-naphthyldiphenylmethyl,p-methoxyphenyldiphenylmethyl, di(p-methoxyphenyl)phenylmethyl,trip-methoxyphenyl)methyl, 4-(4′-bromophenacyloxyphenyl)diphenylmethyl,4,4′,4″-tris(4,5-dichlorophthalimidophenyl)methyl,4,4′,4″-tris(levulinoyloxyphenyl)methyl,4,4′,4″-tris(benzoyloxyphenyl)methyl,3-(imidazol-1-yl)bis(4′,4″-dimethoxyphenyl)methyl,1,1-bis(4-methoxyphenyl)-1′-pyrenylmethyl, 9-anthryl,9-(9-phenyl)xanthenyl, 9-(9-phenyl-10-oxo)anthryl,1,3-benzodithiolan-2-yl, benzisothiazolyl S,S-dioxido, trimethylsilyl(TMS), triethylsilyl (TES), triisopropylsilyl (TIPS),dimethylisopropylsilyl (IPDMS), diethylisopropylsilyl (DEIPS),dimethylthexylsilyl, t-butyldimethylsilyl (TBDMS), t-butyldiphenylsilyl(TBDPS), tribenzylsilyl, tri-p-xylylsilyl, triphenylsilyl,diphenylmethylsilyl (DPMS), t-butylmethoxyphenylsilyl (TBMPS), formate,benzoylformate, acetate, chloroacetate, dichloroacetate,trichloroacetate, trifluoroacetate, methoxyacetate,triphenylmethoxyacetate, phenoxyacetate, p-chlorophenoxyacetate,3-phenylpropionate, 4-oxopentanoate (levulinate),4,4-(ethylenedithio)pentanoate (levulinoyldithioacetal), pivaloate,adamantoate, crotonate, 4-methoxycrotonate, benzoate, p-phenylbenzoate,2,4,6-trimethylbenzoate (mesitoate), methyl carbonate, 9-fluorenylmethylcarbonate (Fmoc), ethyl carbonate, 2,2,2-trichloroethyl carbonate(Troc), 2-(trimethylsilyl)ethyl carbonate (TMSEC), 2-(phenylsulfonyl)ethyl carbonate (Psec), 2-(triphenylphosphonio) ethyl carbonate (Peoc),isobutyl carbonate, vinyl carbonate, allyl carbonate, t-butyl carbonate(BOC or Boc), p-nitrophenyl carbonate, benzyl carbonate, p-methoxybenzylcarbonate, 3,4-dimethoxybenzyl carbonate, o-nitrobenzyl carbonate,p-nitrobenzyl carbonate, S-benzyl thiocarbonate, 4-ethoxy-1-napththylcarbonate, methyl dithiocarbonate, 2-iodobenzoate, 4-azidobutyrate,4-nitro-4-methylpentanoate, o-(dibromomethyl)benzoate,2-formylbenzenesulfonate, 2-(methylthiomethoxy)ethyl,4-(methylthiomethoxy)butyrate, 2-(methylthiomethoxymethyl)benzoate,2,6-dichloro-4-methylphenoxyacetate,2,6-dichloro-4-(1,1,3,3-tetramethylbutyl)phenoxyacetate,2,4-bis(1,1-dimethylpropyl)phenoxyacetate, chlorodiphenylacetate,isobutyrate, monosuccinoate, (E)-2-methyl-2-butenoate,o-(methoxyacyl)benzoate, α-naphthoate, nitrate, alkylN,N,N′,N′-tetramethylphosphorodiamidate, alkyl N-phenylcarbamate,borate, dimethylphosphinothioyl, alkyl 2,4-dinitrophenylsulfenate,sulfate, methanesulfonate (mesylate), benzylsulfonate, and tosylate(Ts).

In certain embodiments, the substituent present on an sulfur atom is asulfur protecting group (also referred to as a “thiol protectinggroup”). Sulfur protecting groups include, but are not limited to,—R^(aa), —N(R^(bb))², —C(═O)SR^(aa), —C(═O)R^(aa), —CO₂R^(aa),—C(═O)N(R^(bb))₂, —C(═NR^(bb))R^(aa), —C(═NR^(bb))OR^(aa),—C(═NR^(bb))N(R^(bb))₂, —S(═O)R^(aa), —SO₂R^(aa), —Si(R^(aa))₃,—P(R^(cc))₂, —P(R^(cc))₃, —P(═O)₂R^(aa), —P(═O)(R^(aa))₂,—P(═O)(OR^(cc))₂, —P(═O)₂N(R^(bb))₂, and —P(═O)(NR^(bb))₂, whereinR^(aa), R^(bb), and R^(cc) are as defined herein. Sulfur protectinggroups are well known in the art and include those described in detailin Protecting Groups in Organic Synthesis, T. W. Greene and P. G. M.Wuts, 3^(rd) edition, John Wiley & Sons, 1999, incorporated herein byreference.

The term “leaving group” is given its ordinary meaning in the art ofsynthetic organic chemistry and refers to an atom or a group capable ofbeing displaced by a nucleophile. Examples of suitable leaving groupsinclude, but are not limited to, halogen (such as F, Cl, Br, or I(iodine)), alkoxycarbonyloxy, aryloxycarbonyloxy, alkanesulfonyloxy,arenesulfonyloxy, alkyl-carbonyloxy (e.g., acetoxy), arylcarbonyloxy,aryloxy, methoxy, N,O-dimethylhydroxylamino, pixyl, and haloformates. Insome cases, the leaving group is a sulfonic acid ester, such astoluenesulfonate (tosylate, —OTs), methanesulfonate (mesylate, —OMs),p-bromobenzenesulfonyloxy (brosylate, —OBs), ortrifluoromethanesulfonate (triflate, —OTf). In some cases, the leavinggroup is a brosylate, such as p-bromobenzenesulfonyloxy. In some cases,the leaving group is a nosylate, such as 2-nitrobenzenesulfonyloxy. Insome embodiments, the leaving group is a sulfonate-containing group. Insome embodiments, the leaving group is a tosylate group. The leavinggroup may also be a phosphineoxide (e.g., formed during a Mitsunobureaction) or an internal leaving group such as an epoxide or cyclicsulfate. Other non-limiting examples of leaving groups are water,ammonia, alcohols, ether moieties, thioether moieties, zinc halides,magnesium moieties, diazonium salts, and copper moieties.

A “hydrocarbon chain” refers to a substituted or unsubstituted divalentalkyl, alkenyl, or alkynyl group. A hydrocarbon chain includes (1) oneor more chains of carbon atoms immediately between the two radicals ofthe hydrocarbon chain; (2) optionally one or more hydrogen atoms on thechain(s) of carbon atoms; and (3) optionally one or more substituents(“non-chain substituents,” which are not hydrogen) on the chain(s) ofcarbon atoms. A chain of carbon atoms consists of consecutivelyconnected carbon atoms (“chain atoms”) and does not include hydrogenatoms or heteroatoms. However, a non-chain substituent of a hydrocarbonchain may include any atoms, including hydrogen atoms, carbon atoms, andheteroatoms. For example, hydrocarbon chain —C^(A)H(C^(B)H₂C^(C)H₃)—includes one chain atom C^(A), one hydrogen atom on C^(A), and non-chainsubstituent —(C^(B)H₂C^(C)H₃). The term “C_(x) hydrocarbon chain,”wherein x is a positive integer, refers to a hydrocarbon chain thatincludes x number of chain atom(s) between the two radicals of thehydrocarbon chain. If there is more than one possible value of x, thesmallest possible value of x is used for the definition of thehydrocarbon chain. For example, —CH(C₂H₅)— is a C₁ hydrocarbon chain,and

is a C₃ hydrocarbon chain. When a range of values is used, the meaningof the range is as described herein. For example, a C₃₋₁₀ hydrocarbonchain refers to a hydrocarbon chain where the number of chain atoms ofthe shortest chain of carbon atoms immediately between the two radicalsof the hydrocarbon chain is 3, 4, 5, 6, 7, 8, 9, or 10. A hydrocarbonchain may be saturated (e.g., —(CH₂)₄—). A hydrocarbon chain may also beunsaturated and include one or more C═C and/or C≡C bonds anywhere in thehydrocarbon chain. For instance, —CH═CH—(CH₂)₂—, —CH₂—C≡C—CH₂—, and—C≡C—CH═CH— are all examples of a unsubstituted and unsaturatedhydrocarbon chain. In certain embodiments, the hydrocarbon chain isunsubstituted (e.g., —C≡C— or —(CH₂)₄—). In certain embodiments, thehydrocarbon chain is substituted (e.g., —CH(C₂H₅)— and —CF₂—). Any twosubstituents on the hydrocarbon chain may be joined to form anoptionally substituted carbocyclyl, optionally substituted heterocyclyl,optionally substituted aryl, or optionally substituted heteroaryl ring.For instance,

are all examples of a hydrocarbon chain. In contrast, in certainembodiments,

are not within the scope of the hydrocarbon chains described herein.When a chain atom of a C_(x) hydrocarbon chain is replaced with aheteroatom, the resulting group is referred to as a C_(x) hydrocarbonchain wherein a chain atom is replaced with a heteroatom, as opposed toa C_(x-1) hydrocarbon chain. For example,

is a C₃ hydrocarbon chain wherein one chain atom is replaced with anoxygen atom.

The term “acyl” refers a group wherein the carbon directly attached tothe parent molecule is sp² hybridized, and is substituted with anoxygen, nitrogen, or sulfur atom, e.g., a group selected from ketones(—C(═O)R^(aa)), carboxylic acids (—CO₂H), aldehydes (—CHO), esters(—CO₂R^(aa), —C(═O)SR^(aa), —C(═S)SR^(aa)), amides (—C(═O)N(R^(bb))₂,—C(═O)NR^(bb)SO₂R^(aa), —C(═S)N(R^(bb))₂), and imines(—C(═NR^(bb))R^(aa), —C(═NR^(bb))OR^(aa)), —C(═NR^(bb))N(R^(bb))₂),wherein R^(aa) and R^(bb) are as defined herein.

The term “Lewis acid” refers to a species as defined by IUPAC, that is“a molecular entity (and the corresponding chemical species) that is anelectron-pair acceptor and therefore able to react with a Lewis base toform a Lewis adduct, by sharing the electron pair furnished by the Lewisbase.” Exemplary Lewis acids include, without limitation, borontrifluoride, aluminum trichloride, tin tetrachloride, titaniumtetrachloride, and iron tribromide.

The term “Bronsted acid” refers to a protic or proton-donating species.Exemplary Brønsted acids include, without limitation, acetic acid,triflic acid, hydrochloric acid, and barbituric acid.

The term “pharmaceutically acceptable salt” refers to those salts whichare, within the scope of sound medical judgment, suitable for use incontact with the tissues of humans and lower animals without unduetoxicity, irritation, allergic response and the like, and arecommensurate with a reasonable benefit/risk ratio. Pharmaceuticallyacceptable salts are well known in the art. For example, Berge et al.,describe pharmaceutically acceptable salts in detail in J.Pharmaceutical Sciences, 1977, 66, 1-19, incorporated herein byreference. Pharmaceutically acceptable salts of the compounds of thisdisclosure include those derived from suitable inorganic and organicacids and bases. Examples of pharmaceutically acceptable, nontoxic acidaddition salts are salts of an amino group formed with inorganic acidssuch as hydrochloric acid, hydrobromic acid, phosphoric acid, sulfuricacid, and perchloric acid or with organic acids such as acetic acid,oxalic acid, maleic acid, tartaric acid, citric acid, succinic acid, ormalonic acid or by using other methods known in the art such as ionexchange. Other pharmaceutically acceptable salts include adipate,alginate, ascorbate, aspartate, benzenesulfonate, benzoate, bisulfate,borate, butyrate, camphorate, camphorsulfonate, citrate,cyclopentanepropionate, digluconate, dodecylsulfate, ethanesulfonate,formate, fumarate, glucoheptonate, glycerophosphate, gluconate,hemisulfate, heptanoate, hexanoate, hydroiodide,2-hydroxy-ethanesulfonate, lactobionate, lactate, laurate, laurylsulfate, malate, maleate, malonate, methanesulfonate,2-naphthalenesulfonate, nicotinate, nitrate, oleate, oxalate, palmitate,pamoate, pectinate, persulfate, 3-phenylpropionate, phosphate, picrate,pivalate, propionate, stearate, succinate, sulfate, tartrate,thiocyanate, p-toluenesulfonate, undecanoate, valerate salts, and thelike. Salts derived from appropriate bases include alkali metal,alkaline earth metal, ammonium and N⁺(C₁₋₄ alkyl)₄ ⁻ salts.Representative alkali or alkaline earth metal salts include sodium,lithium, potassium, calcium, magnesium, and the like. Furtherpharmaceutically acceptable salts include, when appropriate, nontoxicammonium, quaternary ammonium, and amine cations formed usingcounterions such as halide, hydroxide, carboxylate, sulfate, phosphate,nitrate, lower alkyl sulfonate, and aryl sulfonate.

The term “solvate” refers to forms of the compound that are associatedwith a solvent, usually by a solvolysis reaction. This physicalassociation may include hydrogen bonding. Conventional solvents includewater, methanol, ethanol, acetic acid, DMSO, THF, diethyl ether, and thelike. The compounds described herein may be prepared, e.g., incrystalline form, and may be solvated. Suitable solvates includepharmaceutically acceptable solvates and further include bothstoichiometric solvates and non-stoichiometric solvates. In certaininstances, the solvate will be capable of isolation, for example, whenone or more solvent molecules are incorporated in the crystal lattice ofa crystalline solid. “Solvate” encompasses both solution-phase andisolatable solvates. Representative solvates include hydrates,ethanolates, and methanolates.

The term “hydrate” refers to a compound that is associated with water.Typically, the number of the water molecules contained in a hydrate of acompound is in a definite ratio to the number of the compound moleculesin the hydrate. Therefore, a hydrate of a compound may be represented,for example, by the general formula R·x H₂O, wherein R is the compound,and x is a number greater than 0. A given compound may form more thanone type of hydrate, including, e.g., monohydrates (x is 1), lowerhydrates (x is a number greater than 0 and smaller than 1, e.g.,hemihydrates (R·0.5 H₂O)), and polyhydrates (x is a number greater than1, e.g., dihydrates (R·2 H₂O) and hexahydrates (R·6 H₂O)).

The term “tautomers” or “tautomeric” refers to two or moreinterconvertable compounds resulting from at least one formal migrationof a hydrogen atom and at least one change in valency (e.g., a singlebond to a double bond, a triple bond to a single bond, or vice versa).The exact ratio of the tautomers depends on several factors, includingtemperature, solvent, and pH. Tautomerizations (i.e., the reactionproviding a tautomeric pair) may catalyzed by acid or base. Exemplarytautomerizations include keto-to-enol, amide-to-imide, lactam-to-lactim,enamine-to-imine, and enamine-to-(a different enamine) tautomerizations.

It is also to be understood that compounds that have the same molecularformula but differ in the nature or sequence of bonding of their atomsor the arrangement of their atoms in space are termed “isomers”. Isomersthat differ in the arrangement of their atoms in space are termed“stereoisomers”.

Stereoisomers that are not mirror images of one another are termed“diastereomers” and those that are non-superimposable minor images ofeach other are termed “enantiomers”. When a compound has an asymmetriccenter, for example, it is bonded to four different groups, a pair ofenantiomers is possible. An enantiomer can be characterized by theabsolute configuration of its asymmetric center and is described by theR- and S-sequencing rules of Cahn and Prelog, or by the manner in whichthe molecule rotates the plane of polarized light and designated asdextrorotatory or levorotatory (i.e., as (+) or (−)-isomersrespectively). A chiral compound can exist as either individualenantiomer or as a mixture thereof. A mixture containing equalproportions of the enantiomers is called a “racemic mixture”.

The term “polymorphs” refers to a crystalline form of a compound (or asalt, hydrate, or solvate thereof) in a particular crystal packingarrangement. All polymorphs have the same elemental composition.Different crystalline forms usually have different X-ray diffractionpatterns, infrared spectra, melting points, density, hardness, crystalshape, optical and electrical properties, stability, and solubility.Recrystallization solvent, rate of crystallization, storage temperature,and other factors may cause one crystal form to dominate. Variouspolymorphs of a compound can be prepared by crystallization underdifferent conditions.

The term “prodrugs” refer to compounds which have cleavable groups andbecome by solvolysis or under physiological conditions the compoundsdescribed herein, which are pharmaceutically active in vivo. Suchexamples include, but are not limited to, choline ester derivatives andthe like, N-alkylmorpholine esters and the like. Other derivatives ofthe compounds described herein have activity in both their acid and acidderivative forms, but in the acid sensitive form often offer advantagesof solubility, tissue compatibility, or delayed release in the mammalianorganism (see, Bundgard, H., Design of Prodrugs, pp. 7-9, 21-24,Elsevier, Amsterdam 1985). Prodrugs include acid derivatives well knownto practitioners of the art, such as, for example, esters prepared byreaction of the parent acid with a suitable alcohol, or amides preparedby reaction of the parent acid compound with a substituted orunsubstituted amine, or acid anhydrides, or mixed anhydrides. Simplealiphatic or aromatic esters, amides, and anhydrides derived from acidicgroups pendant on the compounds described herein are particularprodrugs. In some cases it is desirable to prepare double ester typeprodrugs such as (acyloxy)alkyl esters or((alkoxycarbonyl)oxy)alkylesters. C₁-C₈ alkyl, C₂-C₈ alkenyl, C₂-C₈alkynyl, aryl, C₇-C₁₂ substituted aryl, and C₇-C₁₂ arylalkyl esters ofthe compounds described herein may be preferred.

The terms “composition” and “formulation” are used interchangeably.

A “subject” to which administration is contemplated includes, but is notlimited to, humans (i.e., a male or female of any age group, e.g., apediatric subject (e.g., infant, child, adolescent) or adult subject(e.g., young adult, middle-aged adult, or senior adult)) and/or othernon-human animals, for example, mammals (e.g., primates (e.g.,cynomolgus monkeys, rhesus monkeys); commercially relevant mammals suchas cattle, pigs, horses, sheep, goats, cats, and/or dogs) and birds(e.g., commercially relevant birds such as chickens, ducks, geese,and/or turkeys). In certain embodiments, the animal is a mammal. Theanimal may be a male or female at any stage of development. The animalmay be a transgenic animal or genetically engineered animal. In certainembodiments, the subject is a non-human animal. In certain embodiments,the animal is a fish or reptile. A “patient” refers to a human subjectin need of treatment of a disease.

The term “administer,” “administering,” or “administration” refers toimplanting, absorbing, ingesting, injecting, inhaling, or otherwiseintroducing a compound described herein, or a composition thereof, in oron a subject.

The terms “treatment,” “treat,” and “treating” refer to reversing,alleviating, delaying the onset of, or inhibiting the progress of adisease described herein. In some embodiments, treatment may beadministered after one or more signs or symptoms of the disease havedeveloped or have been observed. In other embodiments, treatment may beadministered in the absence of signs or symptoms of the disease. Forexample, treatment may be administered to a susceptible subject prior tothe onset of symptoms (e.g., in light of a history of symptoms and/or inlight of exposure to a pathogen). Treatment may also be continued aftersymptoms have resolved, for example, to delay or prevent recurrence.

The term “prevent” refers to a prophylactic treatment of a subject whois not and was not with a disease but is at risk of developing thedisease or who was with a disease, is not with the disease, but is atrisk of regression of the disease. In certain embodiments, the subjectis at a higher risk of developing the disease or at a higher risk ofregression of the disease than an average healthy member of apopulation.

The terms “condition,” “disease,” and “disorder” are usedinterchangeably.

An “effective amount” of a compound described herein refers to an amountsufficient to elicit the desired biological response, i.e., treating thecondition. As will be appreciated by those of ordinary skill in thisart, the effective amount of a compound described herein may varydepending on such factors as the desired biological endpoint, thepharmacokinetics of the compound, the condition being treated, the modeof administration, and the age and health of the subject. An effectiveamount encompasses therapeutic and prophylactic treatment.

A “therapeutically effective amount” of a compound described herein isan amount sufficient to provide a therapeutic benefit in the treatmentof a condition or to delay or minimize one or more symptoms associatedwith the condition. A therapeutically effective amount of a compoundmeans an amount of therapeutic agent, alone or in combination with othertherapies, which provides a therapeutic benefit in the treatment of thecondition. The term “therapeutically effective amount” can encompass anamount that improves overall therapy, reduces or avoids symptoms, signs,or causes of the condition, and/or enhances the therapeutic efficacy ofanother therapeutic agent.

A “prophylactically effective amount” of a compound described herein isan amount sufficient to prevent a condition, or one or more symptomsassociated with the condition or prevent its recurrence. Aprophylactically effective amount of a compound means an amount of atherapeutic agent, alone or in combination with other agents, whichprovides a prophylactic benefit in the prevention of the condition. Theterm “prophylactically effective amount” can encompass an amount thatimproves overall prophylaxis or enhances the prophylactic efficacy ofanother prophylactic agent.

The term “inhibition”, “inhibiting”, “inhibit,” or “inhibitor” refer tothe ability of a compound to reduce, slow, halt, or prevent activity ofa particular biological process (e.g., kinase activity) in a cellrelative to vehicle.

When a compound, pharmaceutical composition, method, use, or kit isreferred to as “selectively” or “specifically” modulating (e.g.,increasing or inhibiting) the activity of a first protein kinase, thecompound, pharmaceutical composition, method, use, or kit modulates theactivity of the first protein kinase to a greater extent (e.g., not lessthan about 2-fold, not less than about 5-fold, not less than about10-fold, not less than about 30-fold, not less than about 100-fold, notless than about 1,000-fold, or not less than about 10,000-fold) than theactivity of at least a second protein kinase that is different from thefirst protein kinase.

A “proliferative disease” refers to a disease that occurs due toabnormal growth or extension by the multiplication of cells (Walker,Cambridge Dictionary of Biology; Cambridge University Press: Cambridge,UK, 1990). A proliferative disease may be associated with: 1) thepathological proliferation of normally quiescent cells; 2) thepathological migration of cells from their normal location (e.g.,metastasis of neoplastic cells); 3) the pathological expression ofproteolytic enzymes such as the matrix metalloproteinases (e.g.,collagenases, gelatinases, and elastases); or 4) the pathologicalangiogenesis as in proliferative retinopathy and tumor metastasis.Exemplary proliferative diseases include cancers (i.e., “malignantneoplasms”), benign neoplasms, angiogenesis, inflammatory diseases, andautoimmune diseases.

The terms “neoplasm” and “tumor” are used herein interchangeably andrefer to an abnormal mass of tissue wherein the growth of the masssurpasses and is not coordinated with the growth of a normal tissue. Aneoplasm or tumor may be “benign” or “malignant,” depending on thefollowing characteristics: degree of cellular differentiation (includingmorphology and functionality), rate of growth, local invasion, andmetastasis. A “benign neoplasm” is generally well differentiated, hascharacteristically slower growth than a malignant neoplasm, and remainslocalized to the site of origin. In addition, a benign neoplasm does nothave the capacity to infiltrate, invade, or metastasize to distantsites. Exemplary benign neoplasms include, but are not limited to,lipoma, chondroma, adenomas, acrochordon, senile angiomas, seborrheickeratoses, lentigos, and sebaceous hyperplasias. In some cases, certain“benign” tumors may later give rise to malignant neoplasms, which mayresult from additional genetic changes in a subpopulation of the tumor'sneoplastic cells, and these tumors are referred to as “pre-malignantneoplasms.” An exemplary pre-malignant neoplasm is a teratoma. Incontrast, a “malignant neoplasm” is generally poorly differentiated(anaplasia) and has characteristically rapid growth accompanied byprogressive infiltration, invasion, and destruction of the surroundingtissue. Furthermore, a malignant neoplasm generally has the capacity tometastasize to distant sites. The term “metastasis,” “metastatic,” or“metastasize” refers to the spread or migration of cancerous cells froma primary or original tumor to another organ or tissue and is typicallyidentifiable by the presence of a “secondary tumor” or “secondary cellmass” of the tissue type of the primary or original tumor and not ofthat of the organ or tissue in which the secondary (metastatic) tumor islocated. For example, a prostate cancer that has migrated to bone issaid to be metastasized prostate cancer and includes cancerous prostatecancer cells growing in bone tissue.

The term “cancer” refers to a class of diseases characterized by thedevelopment of abnormal cells that proliferate uncontrollably and havethe ability to infiltrate and destroy normal body tissues. See, e.g.,Stedman's Medical Dictionary, 25th ed.; Hensyl ed.; Williams & Wilkins:Philadelphia, 1990. Exemplary cancers include, but are not limited to,acoustic neuroma; adenocarcinoma; adrenal gland cancer; anal cancer;angiosarcoma (e.g., lymphangiosarcoma, lymphangioendotheliosarcoma,hemangiosarcoma); appendix cancer; benign monoclonal gammopathy; biliarycancer (e.g., cholangiocarcinoma); bladder cancer; breast cancer (e.g.,adenocarcinoma of the breast, papillary carcinoma of the breast, mammarycancer, medullary carcinoma of the breast); brain cancer (e.g.,meningioma, glioblastomas, glioma (e.g., astrocytoma,oligodendroglioma), medulloblastoma); bronchus cancer; carcinoid tumor;cervical cancer (e.g., cervical adenocarcinoma); choriocarcinoma;chordoma; craniopharyngioma; colorectal cancer (e.g., colon cancer,rectal cancer, colorectal adenocarcinoma); connective tissue cancer;epithelial carcinoma; ependymoma; endotheliosarcoma (e.g., Kaposi'ssarcoma, multiple idiopathic hemorrhagic sarcoma); endometrial cancer(e.g., uterine cancer, uterine sarcoma); esophageal cancer (e.g.,adenocarcinoma of the esophagus, Barrett's adenocarcinoma); Ewing'ssarcoma; ocular cancer (e.g., intraocular melanoma, retinoblastoma);familiar hypereosinophilia; gall bladder cancer; gastric cancer (e.g.,stomach adenocarcinoma); gastrointestinal stromal tumor (GIST); germcell cancer; head and neck cancer (e.g., head and neck squamous cellcarcinoma, oral cancer (e.g., oral squamous cell carcinoma), throatcancer (e.g., laryngeal cancer, pharyngeal cancer, nasopharyngealcancer, oropharyngeal cancer)); hematopoietic cancers (e.g., leukemiasuch as acute lymphocytic leukemia (ALL) (e.g., B-cell ALL, T-cell ALL),acute myelocytic leukemia (AML) (e.g., B-cell AML, T-cell AML), chronicmyelocytic leukemia (CML) (e.g., B-cell CML, T-cell CML), and chroniclymphocytic leukemia (CLL) (e.g., B-cell CLL, T-cell CLL)); lymphomasuch as Hodgkin lymphoma (HL) (e.g., B-cell HL, T-cell HL) andnon-Hodgkin lymphoma (NHL) (e.g., B-cell NHL such as diffuse large celllymphoma (DLCL) (e.g., diffuse large B-cell lymphoma), follicularlymphoma, chronic lymphocytic leukemia/small lymphocytic lymphoma(CLL/SLL), mantle cell lymphoma (MCL), marginal zone B-cell lymphomas(e.g., mucosa-associated lymphoid tissue (MALT) lymphomas, nodalmarginal zone B-cell lymphoma, splenic marginal zone B-cell lymphoma),primary mediastinal B-cell lymphoma, Burkitt lymphoma, lymphoplasmacyticlymphoma (i.e., Waldenström's macroglobulinemia), hairy cell leukemia(HCL), immunoblastic large cell lymphoma, precursor B-lymphoblasticlymphoma and primary central nervous system (CNS) lymphoma; and T-cellNHL such as precursor T-lymphoblastic lymphoma/leukemia, peripheralT-cell lymphoma (PTCL) (e.g., cutaneous T-cell lymphoma (CTCL) (e.g.,mycosis fungoides, Sezary syndrome), angioimmunoblastic T-cell lymphoma,extranodal natural killer T-cell lymphoma, enteropathy type T-celllymphoma, subcutaneous panniculitis-like T-cell lymphoma, and anaplasticlarge cell lymphoma); a mixture of one or more leukemia/lymphoma asdescribed above; and multiple myeloma (MM)), heavy chain disease (e.g.,alpha chain disease, gamma chain disease, mu chain disease);hemangioblastoma; hypopharynx cancer; inflammatory myofibroblastictumors; immunocytic amyloidosis; kidney cancer (e.g., nephroblastomaa.k.a. Wilms' tumor, renal cell carcinoma); liver cancer (e.g.,hepatocellular cancer (HCC), malignant hepatoma); lung cancer (e.g.,bronchogenic carcinoma, small cell lung cancer (SCLC), non-small celllung cancer (NSCLC), adenocarcinoma of the lung); leiomyosarcoma (LMS);mastocytosis (e.g., systemic mastocytosis); muscle cancer;myelodysplastic syndrome (MDS); mesothelioma; myeloproliferativedisorder (MPD) (e.g., polycythemia vera (PV), essential thrombocytosis(ET), agnogenic myeloid metaplasia (AMM) a.k.a. myelofibrosis (MF),chronic idiopathic myelofibrosis, chronic myelocytic leukemia (CML),chronic neutrophilic leukemia (CNL), hypereosinophilic syndrome (HES));neuroblastoma; neurofibroma (e.g., neurofibromatosis (NF) type 1 or type2, schwannomatosis); neuroendocrine cancer (e.g., gastroenteropancreaticneuroendoctrine tumor (GEP-NET), carcinoid tumor); osteosarcoma (e.g.,bone cancer); ovarian cancer (e.g., cystadenocarcinoma, ovarianembryonal carcinoma, ovarian adenocarcinoma); papillary adenocarcinoma;pancreatic cancer (e.g., pancreatic andenocarcinoma, intraductalpapillary mucinous neoplasm (IPMN), Islet cell tumors); penile cancer(e.g., Paget's disease of the penis and scrotum); pinealoma; primitiveneuroectodermal tumor (PNT); plasma cell neoplasia; paraneoplasticsyndromes; intraepithelial neoplasms; prostate cancer (e.g., prostateadenocarcinoma); rectal cancer; rhabdomyosarcoma; salivary gland cancer;skin cancer (e.g., squamous cell carcinoma (SCC), keratoacanthoma (KA),melanoma, basal cell carcinoma (BCC)); small bowel cancer (e.g.,appendix cancer); soft tissue sarcoma (e.g., malignant fibroushistiocytoma (MFH), liposarcoma, malignant peripheral nerve sheath tumor(MPNST), chondrosarcoma, fibrosarcoma, myxosarcoma); sebaceous glandcarcinoma; small intestine cancer; sweat gland carcinoma; synovioma;testicular cancer (e.g., seminoma, testicular embryonal carcinoma);thyroid cancer (e.g., papillary carcinoma of the thyroid, papillarythyroid carcinoma (PTC), medullary thyroid cancer); urethral cancer;vaginal cancer; and vulvar cancer (e.g., Paget's disease of the vulva).

Detailed Description of Certain Embodiments of the Invention

The present invention provides the first synthesis of halichondrin A,and analogs thereof, and analogs of norhalichondrin A andhomohalichondrin A. The present invention provides methods of preparingthese compounds and their analogs along with various intermediates usedin these syntheses. The synthetic routes presented herein include: (1)synthesis of a C1-C19 building block via a catalytic asymmetricchromium-mediated coupling; (2) synthesis of the macrocyclic core via anasymmetric nickel/chromium-mediated coupling, followed by base-inducedfuran formation, and macrolactonization; (3) synthesis of an unsaturatedketone intermediate via nickel/chromium-mediated coupling, followed byDess-Martin oxidation; and (4) a newly discovered, highly selectiveacid-mediated equilibration of C38-epi-halichondrin A to halichondrin A.In addition, the structure of these compounds including halichondrin Ahas been determined unambiguously. The present invention also providespharmaceutical compositions comprising any of the halichondrin A,norhalichondrin A, or homohalichondrin A analogs described herein, andoptionally a pharmaceutically acceptable excipient. These pharmaceuticalcompositions may be useful for treating and/or preventing aproliferative disease (e.g., cancer) in a subject in need thereof. Thepresent invention also provides kits comprising a container with acompound described herein, or a pharmaceutical composition thereof.

As generally described herein, provided are halichondrin A and analogsthereof of Formula (I):

and pharmaceutically acceptable salts thereof,wherein

R^(P1), R^(P2), and R^(P3) are each independently hydrogen, substitutedor unsubstituted alkyl, or an oxygen protecting group;

R¹, R², R³, and R⁵ are each independently hydrogen, halogen, orsubstituted or unsubstituted alkyl;

each instance of R⁴ is independently hydrogen, halogen, substituted orunsubstituted alkyl, or two R⁴ groups can be taken together to form a

group;

each instance of R⁶ is independently hydrogen, halogen, substituted orunsubstituted alkyl, or two R⁶ groups can be taken together to form a

group;

R^(X) is —OR^(X1), wherein R^(X1) is hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group;

R^(Y) is —OR^(Y1), wherein R^(Y1) is hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group; and

R^(X) and R^(Y) can be taken with their intervening atoms to form asubstituted or unsubstituted heterocyclic ring.

In another aspect, provided are norhalichondrin A analogs of Formula(II):

and pharmaceutically acceptable salts thereof,wherein

R^(P8) is hydrogen, substituted or unsubstituted alkyl, or an oxygenprotecting group;

R¹, R², R³, and R⁵ are each independently hydrogen, halogen, orsubstituted or unsubstituted alkyl;

each instance of R⁴ is independently hydrogen, halogen, substituted orunsubstituted alkyl, or two R⁴ groups can be taken together to form a

group;

each instance of R⁶ is independently hydrogen, halogen, substituted orunsubstituted alkyl, or two R⁶ groups can be taken together to form a

group;

R⁷ is hydrogen, substituted or unsubstituted alkyl, or an oxygenprotecting group;

R^(X) is —OR^(X1), wherein R^(X1) is hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group;

R^(Y) is —OR^(Y1), wherein R^(Y1) is hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group; and

R^(X) and R^(Y) can be taken with their intervening atoms to form asubstituted or unsubstituted heterocyclic ring;

-   -   provided that a compound of Formula (II) is not norhalichondrin        A:

In another aspect, provided are homohalichondrin A analogs of Formula(III):

and pharmaceutically acceptable salts thereof,wherein

R^(P12) and R^(P13) are each independently hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group;

R¹, R², R³, and R⁵ are each independently hydrogen, halogen, orsubstituted or unsubstituted alkyl;

each instance of R⁴ is independently hydrogen, halogen, substituted orunsubstituted alkyl, or two R⁴ groups can be taken together to form a

group;

each instance of R⁶ is independently hydrogen, halogen, substituted orunsubstituted alkyl, or two R⁶ groups can be taken together to form a

group;

R^(X) is —OR^(X1), wherein R^(X1) is hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group;

R^(Y) is —OR^(Y1), wherein R^(Y1) is hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group; and

R^(X) and R^(Y) can be taken with their intervening atoms to form asubstituted or unsubstituted heterocyclic ring;

provided that a compound of Formula (III) is not homohalichondrin A:

Groups R^(P1), R^(P2), R^(P3), R^(P4), R^(P5), R^(P6), R^(P7), R^(P8),R^(P9), R^(P10), R^(P11), R^(P12), R^(P13), R^(P14), R^(P15), R^(P16),R^(P17), R^(P18), and R^(P19)

As generally described herein, R^(P1), R^(P2), R^(P3), R^(P4), R^(P5),R^(P6), R^(P7), R^(P8), R^(P9), R^(P10), R^(P11), R^(P12), R^(P13),R^(P14), R^(P15), R^(P16), R^(P17), R^(P18), and R^(P19) are eachindependently hydrogen, substituted or unsubstituted alkyl, or an oxygenprotecting group.

In certain embodiments, R^(P1) is hydrogen. In certain embodiments,R^(P1) is substituted or unsubstitituted alkyl. In certain embodiments,R^(P1) is substituted or unsubstituted C₁₋₆ alkyl. In certainembodiments, R^(P1) is substituted or unsubstituted, branched C₁₋₆alkyl. In certain embodiments, R^(P1) is unsubstituted C₁₋₆ alkyl. Incertain embodiments, R^(P1) is methyl. In certain embodiments, R^(P1) isethyl. In certain embodiments, R^(P1) is propyl. In certain embodiments,R^(P1) is iso-propyl. In certain embodiments, R^(P1) is t-butyl. Incertain embodiments, R^(P1) is an oxygen protecting group. In certainembodiments, R^(P1) is a silyl protecting group. In certain embodiments,R^(P1) is a trialkyl silyl protecting group. In certain embodiments,R^(P1) is a t-butyldimethylsilyl protecting group. In certainembodiments, R^(P1) is a trimethylsilyl protecting group. In certainembodiments, R^(P1) is a triethylsilyl protecting group. In certainembodiments, R^(P1) is a t-butyldiphenylsilyl protecting group. Incertain embodiments, R^(P1) is a triisopropylsilyl protecting group. Incertain embodiments, R^(P1) is a benzylic protecting group. In certainembodiments, R^(P1) is a p-methoxybenzyl protecting group. In certainembodiments, R^(P1) is an acyl protecting group. In certain embodiments,R^(P1) is an acetyl protecting group. In certain embodiments, R^(P1) isa benzoyl protecting group. In certain embodiments, R^(P1) is a p-nitrobenzoyl protecting group. In certain embodiments, R^(P1) is a pivaloylprotecting group. In certain embodiments, R^(P1) is a t-butyl carbonate(BOC) protecting group. In certain embodiments, R^(P1) is an acetalprotecting group. In certain embodiments, R^(P1) is a tetrahydropyranylprotecting group. In certain embodiments, R^(P1) is an alkoxyalkylprotecting group. In certain embodiments, R^(P1) is an ethoxyethylprotecting group.

In certain embodiments, R^(P2) is hydrogen. In certain embodiments,R^(P2) is substituted or unsubstitituted alkyl. In certain embodiments,R^(P2) is substituted or unsubstituted C₁₋₆ alkyl. In certainembodiments, R^(P2) is substituted or unsubstituted, branched C₁₋₆alkyl. In certain embodiments, R^(P2) is unsubstituted C₁₋₆ alkyl. Incertain embodiments, R^(P2) is methyl. In certain embodiments, R^(P2) isethyl. In certain embodiments, R^(P2) is propyl. In certain embodiments,R^(P2) is iso-propyl. In certain embodiments, R^(P2) is t-butyl. Incertain embodiments, R^(P2) is an oxygen protecting group. In certainembodiments, R^(P2) is a silyl protecting group. In certain embodiments,R^(P2) is a trialkyl silyl protecting group. In certain embodiments,R^(P2) is a t-butyldimethylsilyl protecting group. In certainembodiments, R^(P2) is a trimethylsilyl protecting group. In certainembodiments, R^(P2) is a triethylsilyl protecting group. In certainembodiments, R^(P2) is a t-butyldiphenylsilyl protecting group. Incertain embodiments, R^(P2) is a triisopropylsilyl protecting group. Incertain embodiments, R^(P2) is a benzylic protecting group. In certainembodiments, R^(P2) is a p-methoxybenzyl protecting group. In certainembodiments, R^(P2) is an acyl protecting group. In certain embodiments,R^(P2) is an acetyl protecting group. In certain embodiments, R^(P2) isa benzoyl protecting group. In certain embodiments, R^(P2) is a p-nitrobenzoyl protecting group. In certain embodiments, R^(P2) is a pivaloylprotecting group. In certain embodiments, R^(P2) is a t-butyl carbonate(BOC) protecting group. In certain embodiments, R^(P2) is an acetalprotecting group. In certain embodiments, R^(P2) is a tetrahydropyranylprotecting group. In certain embodiments, R^(P2) is an alkoxyalkylprotecting group. In certain embodiments, R^(P2) is an ethoxyethylprotecting group.

In certain embodiments, R^(P3) is hydrogen. In certain embodiments,R^(P3) is substituted or unsubstitituted alkyl. In certain embodiments,R^(P3) is substituted or unsubstituted C₁₋₆ alkyl. In certainembodiments, R^(P3) is substituted or unsubstituted, branched C₁₋₆alkyl. In certain embodiments, R^(P3) is unsubstituted C₁₋₆ alkyl. Incertain embodiments, R^(P3) is methyl. In certain embodiments, R^(P3) isethyl. In certain embodiments, R^(P3) is propyl. In certain embodiments,R^(P3) is iso-propyl. In certain embodiments, R^(P3) is t-butyl. Incertain embodiments, R^(P3) is an oxygen protecting group. In certainembodiments, R^(P3) is a silyl protecting group. In certain embodiments,R^(P3) is a trialkyl silyl protecting group. In certain embodiments,R^(P3) is a t-butyldimethylsilyl protecting group. In certainembodiments, R^(P3) is a trimethylsilyl protecting group. In certainembodiments, R^(P3) is a triethylsilyl protecting group. In certainembodiments, R^(P3) is a t-butyldiphenylsilyl protecting group. Incertain embodiments, R^(P3) is a triisopropylsilyl protecting group. Incertain embodiments, R^(P3) is a benzylic protecting group. In certainembodiments, R^(P3) is a p-methoxybenzyl protecting group. In certainembodiments, R^(P3) is an acyl protecting group. In certain embodiments,R^(P3) is an acetyl protecting group. In certain embodiments, R^(P3) isa benzoyl protecting group. In certain embodiments, R^(P3) is a p-nitrobenzoyl protecting group. In certain embodiments, R^(P3) is a pivaloylprotecting group. In certain embodiments, R^(P3) is a t-butyl carbonate(BOC) protecting group. In certain embodiments, R^(P3) is an acetalprotecting group. In certain embodiments, R^(P3) is a tetrahydropyranylprotecting group. In certain embodiments, R^(P3) is an alkoxyalkylprotecting group. In certain embodiments, R^(P3) is an ethoxyethylprotecting group.

In certain embodiments, R^(P4) is hydrogen. In certain embodiments,R^(P4) is substituted or unsubstitituted alkyl. In certain embodiments,R^(P4) is substituted or unsubstituted C₁₋₆ alkyl. In certainembodiments, R^(P4) is substituted or unsubstituted, branched C₁₋₆alkyl. In certain embodiments, R^(P4) is unsubstituted C₁₋₆ alkyl. Incertain embodiments, R^(P4) is methyl. In certain embodiments, R^(P4) isethyl. In certain embodiments, R^(P4) is propyl. In certain embodiments,R^(P4) is iso-propyl. In certain embodiments, R^(P4) is t-butyl. Incertain embodiments, R^(P4) is an oxygen protecting group. In certainembodiments, R^(P4) is a silyl protecting group. In certain embodiments,R^(P4) is a trialkyl silyl protecting group. In certain embodiments,R^(P4) is a t-butyldimethylsilyl protecting group. In certainembodiments, R^(P4) is a trimethylsilyl protecting group. In certainembodiments, R^(P4) is a triethylsilyl protecting group. In certainembodiments, R^(P4) is a t-butyldiphenylsilyl protecting group. Incertain embodiments, R^(P4) is a triisopropylsilyl protecting group. Incertain embodiments, R^(P4) is a benzylic protecting group. In certainembodiments, R^(P4) is a p-methoxybenzyl protecting group. In certainembodiments, R^(P4) is an acyl protecting group. In certain embodiments,R^(P4) is an acetyl protecting group. In certain embodiments, R^(P4) isa benzoyl protecting group. In certain embodiments, R^(P4) is a p-nitrobenzoyl protecting group. In certain embodiments, R^(P4) is a pivaloylprotecting group. In certain embodiments, R^(P4) is a t-butyl carbonate(BOC) protecting group. In certain embodiments, R^(P4) is an acetalprotecting group. In certain embodiments, R^(P4) is a tetrahydropyranylprotecting group. In certain embodiments, R^(P4) is an alkoxyalkylprotecting group. In certain embodiments, R^(P4) is an ethoxyethylprotecting group.

In certain embodiments, R^(P5) is hydrogen. In certain embodiments,R^(P5) is substituted or unsubstitituted alkyl. In certain embodiments,R^(P5) is substituted or unsubstituted C₁₋₆ alkyl. In certainembodiments, R^(P5) is substituted or unsubstituted, branched C₁₋₆alkyl. In certain embodiments, R^(P5) is unsubstituted C₁₋₆ alkyl. Incertain embodiments, R^(P5) is methyl. In certain embodiments, R^(P5) isethyl. In certain embodiments, R^(P5) is propyl. In certain embodiments,R^(P5) is iso-propyl. In certain embodiments, R^(P5) is t-butyl. Incertain embodiments, R^(P5) is an oxygen protecting group. In certainembodiments, R^(P5) is a silyl protecting group. In certain embodiments,R^(P5) is a trialkyl silyl protecting group. In certain embodiments,R^(P5) is a t-butyldimethylsilyl protecting group. In certainembodiments, R^(P5) is a trimethylsilyl protecting group. In certainembodiments, R^(P5) is a triethylsilyl protecting group. In certainembodiments, R^(P5) is a t-butyldiphenylsilyl protecting group. Incertain embodiments, R^(P5) is a triisopropylsilyl protecting group. Incertain embodiments, R^(P5) is a benzylic protecting group. In certainembodiments, R^(P5) is a p-methoxybenzyl protecting group. In certainembodiments, R^(P5) is an acyl protecting group. In certain embodiments,R^(P5) is an acetyl protecting group. In certain embodiments, R^(P5) isa benzoyl protecting group. In certain embodiments, R^(P5) is a p-nitrobenzoyl protecting group. In certain embodiments, R^(P5) is a pivaloylprotecting group. In certain embodiments, R^(P5) is a t-butyl carbonate(BOC) protecting group. In certain embodiments, R^(P5) is an acetalprotecting group. In certain embodiments, R^(P5) is a tetrahydropyranylprotecting group. In certain embodiments, R^(P5) is an alkoxyalkylprotecting group. In certain embodiments, R^(P5) is an ethoxyethylprotecting group.

In certain embodiments, R^(P6) is hydrogen. In certain embodiments,R^(P6) is substituted or unsubstitituted alkyl. In certain embodiments,R^(P6) is substituted or unsubstituted C₁₋₆ alkyl. In certainembodiments, R^(P6) is substituted or unsubstituted, branched C₁₋₆alkyl. In certain embodiments, R^(P6) is unsubstituted C₁₋₆ alkyl. Incertain embodiments, R^(P6) is methyl. In certain embodiments, R^(P6) isethyl. In certain embodiments, R^(P6) is propyl. In certain embodiments,R^(P6) is iso-propyl. In certain embodiments, R^(P6) is t-butyl. Incertain embodiments, R^(P6) is an oxygen protecting group. In certainembodiments, R^(P6) is a silyl protecting group. In certain embodiments,R^(P6) is a trialkyl silyl protecting group. In certain embodiments,R^(P6) is a t-butyldimethylsilyl protecting group. In certainembodiments, R^(P6) is a trimethylsilyl protecting group. In certainembodiments, R^(P6) is a triethylsilyl protecting group. In certainembodiments, R^(P6) is a t-butyldiphenylsilyl protecting group. Incertain embodiments, R^(P6) is a triisopropylsilyl protecting group. Incertain embodiments, R^(P6) is a benzylic protecting group. In certainembodiments, R^(P6) is a p-methoxybenzyl protecting group. In certainembodiments, R^(P6) is an acyl protecting group. In certain embodiments,R^(P6) is an acetyl protecting group. In certain embodiments, R^(P6) isa benzoyl protecting group. In certain embodiments, R^(P6) is a p-nitrobenzoyl protecting group. In certain embodiments, R^(P6) is a pivaloylprotecting group. In certain embodiments, R^(P6) is a t-butyl carbonate(BOC) protecting group. In certain embodiments, R^(P6) is an acetalprotecting group. In certain embodiments, R^(P6) is a tetrahydropyranylprotecting group. In certain embodiments, R^(P6) is an alkoxyalkylprotecting group. In certain embodiments, R^(P6) is an ethoxyethylprotecting group.

In certain embodiments, R^(P7) is hydrogen. In certain embodiments,R^(P7) is substituted or unsubstitituted alkyl. In certain embodiments,R^(P7) is substituted or unsubstituted C₁₋₆ alkyl. In certainembodiments, R^(P7) is substituted or unsubstituted, branched C₁₋₆alkyl. In certain embodiments, R^(P7) is unsubstituted C₁₋₆ alkyl. Incertain embodiments, R^(P7) is methyl. In certain embodiments, R^(P7) isethyl. In certain embodiments, R^(P7) is propyl. In certain embodiments,R^(P7) is iso-propyl. In certain embodiments, R^(P7) is t-butyl. Incertain embodiments, R^(P7) is an oxygen protecting group. In certainembodiments, R^(P7) is a silyl protecting group. In certain embodiments,R^(P7) is a trialkyl silyl protecting group. In certain embodiments,R^(P7) is a t-butyldimethylsilyl protecting group. In certainembodiments, R^(P7) is a trimethylsilyl protecting group. In certainembodiments, R^(P7) is a triethylsilyl protecting group. In certainembodiments, R^(P7) is a t-butyldiphenylsilyl protecting group. Incertain embodiments, R^(P7) is a triisopropylsilyl protecting group. Incertain embodiments, R^(P7) is a benzylic protecting group. In certainembodiments, R^(P7) is a p-methoxybenzyl protecting group. In certainembodiments, R^(P7) is an acyl protecting group. In certain embodiments,R^(P7) is an acetyl protecting group. In certain embodiments, R^(P7) isa benzoyl protecting group. In certain embodiments, R^(P7) is a p-nitrobenzoyl protecting group. In certain embodiments, R^(P7) is a pivaloylprotecting group. In certain embodiments, R^(P7) is a t-butyl carbonate(BOC) protecting group. In certain embodiments, R^(P7) is an acetalprotecting group. In certain embodiments, R^(P7) is a tetrahydropyranylprotecting group. In certain embodiments, R^(P7) is an alkoxyalkylprotecting group. In certain embodiments, R^(P7) is an ethoxyethylprotecting group.

In certain embodiments, R^(P8) is hydrogen. In certain embodiments,R^(P8) is substituted or unsubstitituted alkyl. In certain embodiments,R^(P8) is substituted or unsubstituted C₁₋₆ alkyl. In certainembodiments, R^(P8) is substituted or unsubstituted, branched C₁₋₆alkyl. In certain embodiments, R^(P8) is unsubstituted C₁₋₆ alkyl. Incertain embodiments, R^(P8) is methyl. In certain embodiments, R^(P8) isethyl. In certain embodiments, R^(P8) is propyl. In certain embodiments,R^(P8) is iso-propyl. In certain embodiments, R^(P8) is t-butyl. Incertain embodiments, R^(P8) is an oxygen protecting group. In certainembodiments, R^(P8) is a silyl protecting group. In certain embodiments,R^(P8) is a trialkyl silyl protecting group. In certain embodiments,R^(P8) is a t-butyldimethylsilyl protecting group. In certainembodiments, R^(P8) is a trimethylsilyl protecting group. In certainembodiments, R^(P8) is a triethylsilyl protecting group. In certainembodiments, R^(P8) is a t-butyldiphenylsilyl protecting group. Incertain embodiments, R^(P8) is a triisopropylsilyl protecting group. Incertain embodiments, R^(P8) is a benzylic protecting group. In certainembodiments, R^(P8) is a p-methoxybenzyl protecting group. In certainembodiments, R^(P8) is an acyl protecting group. In certain embodiments,R^(P8) is an acetyl protecting group. In certain embodiments, R^(P8) isa benzoyl protecting group. In certain embodiments, R^(P8) is a p-nitrobenzoyl protecting group. In certain embodiments, R^(P8) is a pivaloylprotecting group. In certain embodiments, R^(P8) is a t-butyl carbonate(BOC) protecting group. In certain embodiments, R^(P8) is an acetalprotecting group. In certain embodiments, R^(P8) is a tetrahydropyranylprotecting group. In certain embodiments, R^(P8) is an alkoxyalkylprotecting group. In certain embodiments, R^(P8) is an ethoxyethylprotecting group.

In certain embodiments, R^(P9) is hydrogen. In certain embodiments,R^(P9) is substituted or unsubstitituted alkyl. In certain embodiments,R^(P9) is substituted or unsubstituted C₁₋₆ alkyl. In certainembodiments, R^(P9) is substituted or unsubstituted, branched C₁₋₆alkyl. In certain embodiments, R^(P9) is unsubstituted C₁₋₆ alkyl. Incertain embodiments, R^(P9) is methyl. In certain embodiments, R^(P9) isethyl. In certain embodiments, R^(P9) is propyl. In certain embodiments,R^(P9) is iso-propyl. In certain embodiments, R^(P9) is t-butyl. Incertain embodiments, R^(P9) is an oxygen protecting group. In certainembodiments, R^(P9) is a silyl protecting group. In certain embodiments,R^(P9) is a trialkyl silyl protecting group. In certain embodiments,R^(P9) is a t-butyldimethylsilyl protecting group. In certainembodiments, R^(P9) is a trimethylsilyl protecting group. In certainembodiments, R^(P9) is a triethylsilyl protecting group. In certainembodiments, R^(P9) is a t-butyldiphenylsilyl protecting group. Incertain embodiments, R^(P9) is a triisopropylsilyl protecting group. Incertain embodiments, R^(P9) is a benzylic protecting group. In certainembodiments, R^(P9) is a p-methoxybenzyl protecting group. In certainembodiments, R^(P9) is an acyl protecting group. In certain embodiments,R^(P9) is an acetyl protecting group. In certain embodiments, R^(P9) isa benzoyl protecting group. In certain embodiments, R^(P9) is a p-nitrobenzoyl protecting group. In certain embodiments, R^(P9) is a pivaloylprotecting group. In certain embodiments, R^(P9) is a t-butyl carbonate(BOC) protecting group. In certain embodiments, R^(P9) is an acetalprotecting group. In certain embodiments, R^(P9) is a tetrahydropyranylprotecting group. In certain embodiments, R^(P9) is an alkoxyalkylprotecting group. In certain embodiments, R^(P9) is an ethoxyethylprotecting group.

In certain embodiments, R^(P10) is hydrogen. In certain embodiments,R^(P10) is substituted or unsubstitituted alkyl. In certain embodiments,R^(P10) is substituted or unsubstituted C₁₋₆ alkyl. In certainembodiments, R^(P10) is substituted or unsubstituted, branched C₁₋₆alkyl. In certain embodiments, R^(P10) is unsubstituted C₁₋₆ alkyl. Incertain embodiments, R^(P10) is methyl. In certain embodiments, R^(P10)is ethyl. In certain embodiments, R^(P10) is propyl. In certainembodiments, R^(P10) is iso-propyl. In certain embodiments, R^(P10) ist-butyl. In certain embodiments, R^(P10) is an oxygen protecting group.In certain embodiments, R^(P10) is a silyl protecting group. In certainembodiments, R^(P10) is a trialkyl silyl protecting group. In certainembodiments, R^(P10) is a t-butyldimethylsilyl protecting group. Incertain embodiments, R^(P10) is a trimethylsilyl protecting group. Incertain embodiments, R^(P10) is a triethylsilyl protecting group. Incertain embodiments, R^(P10) is a t-but protecting group. In certainembodiments, R^(P10) is a triisopropylsilyl protecting group. In certainembodiments, R^(P10) is a benzylic protecting group. In certainembodiments, R^(P10) is a p-methoxybenzyl protecting group. In certainembodiments, R^(P10) is an acyl protecting group. In certainembodiments, R^(P10) is an acetyl protecting group. In certainembodiments, R^(P10) is a benzoyl protecting group. In certainembodiments, R^(P10) is a p-nitro benzoyl protecting group. In certainembodiments, R^(P10) is a pivaloyl protecting group. In certainembodiments, R^(P10) is a t-butyl carbonate (BOC) protecting group. Incertain embodiments, R^(P10) is an acetal protecting group. In certainembodiments, R^(P10) is a tetrah dropyranyl protecting group. In certainembodiments, R^(P10) is an alkoxyalkyl protecting group. In certainembodiments, R^(P10) is an ethoxyethyl protecting group.

In certain embodiments, R^(P11) is hydrogen. In certain embodiments,R^(P11) is substituted or unsubstitituted alkyl. In certain embodiments,R^(P11) is substituted or unsubstituted C₁₋₆ alkyl. In certainembodiments, R^(P11) is substituted or unsubstituted, branched C₁₋₆alkyl. In certain embodiments, R^(P11) is unsubstituted C₁₋₆ alkyl. Incertain embodiments, R^(P11) is methyl. In certain embodiments, R^(P11)is ethyl. In certain embodiments, R^(P11) is propyl. In certainembodiments, R^(P11) is iso-propyl. In certain embodiments, R^(P11) ist-butyl. In certain embodiments, R^(P11) is an oxygen protecting group.In certain embodiments, R^(P11) is a silyl protecting group. In certainembodiments, R^(P11) is a trialkyl silyl protecting group. In certainembodiments, R^(P11) is a t-butyldimethylsilyl protecting group. Incertain embodiments, R^(P11) is a trimethylsilyl protecting group. Incertain embodiments, R^(P11) is a triethylsilyl protecting group. Incertain embodiments, R^(P11) is a t-butyldiphenylsilyl protecting group.In certain embodiments, R^(P11) is a triisopropylsilyl protecting group.In certain embodiments, R^(P11) is a benzylic protecting group. Incertain embodiments, R^(P11) is a p-methoxybenzyl protecting group. Incertain embodiments, R^(P11) is an acyl protecting group. In certainembodiments, R^(P11) is an acetyl protecting group. In certainembodiments, R^(P11) is a benzoyl protecting group. In certainembodiments, R^(P11) is a p-nitro benzoyl protecting group. In certainembodiments, R^(P11) is a pivaloyl protecting group. In certainembodiments, R^(P11) is a t-butyl carbonate (BOC) protecting group. Incertain embodiments, R^(P11) is an acetal protecting group. In certainembodiments, R^(P11) is a tetrahydropyranyl protecting group. In certainembodiments, R^(P11) is an alkoxyalkyl protecting group. In certainembodiments, R^(P11) is an ethoxyethyl protecting group.

In certain embodiments, R^(P12) is hydrogen. In certain embodiments,R^(P12) is substituted or unsubstitituted alkyl. In certain embodiments,R^(P12) is substituted or unsubstituted C₁₋₆ alkyl. In certainembodiments, R^(P12) is substituted or unsubstituted, branched C₁₋₆alkyl. In certain embodiments, R^(P12) is unsubstituted C₁₋₆ alkyl. Incertain embodiments, R^(P12) is methyl. In certain embodiments, R^(P12)is ethyl. In certain embodiments, R^(P12) is propyl. In certainembodiments, R^(P12) is iso-propyl. In certain embodiments, R^(P12) ist-butyl. In certain embodiments, R^(P12) is an oxygen protecting group.In certain embodiments, R^(P12) is a silyl protecting group. In certainembodiments, R^(P12) is a trialkyl silyl protecting group. In certainembodiments, R^(P12) is a t-butyldimethylsilyl protecting group. Incertain embodiments, R^(P12) is a trimethylsilyl protecting group. Incertain embodiments, R^(P12) is a triethylsilyl protecting group. Incertain embodiments, R^(P12) is a t-butyldiphenylsilyl protecting group.In certain embodiments, R^(P12) is a triisopropylsilyl protecting group.In certain embodiments, R^(P12) is a benzylic protecting group. Incertain embodiments, R^(P12) is a p-methoxybenzyl protecting group. Incertain embodiments, R^(P12) is an acyl protecting group. In certainembodiments, R^(P12) is an acetyl protecting group. In certainembodiments, R^(P12) is a benzoyl protecting group. In certainembodiments, R^(P12) is a p-nitro benzoyl protecting group. In certainembodiments, R^(P12) is a pivaloyl protecting group. In certainembodiments, R^(P12) is a t-butyl carbonate (BOC) protecting group. Incertain embodiments, R^(P12) is an acetal protecting group. In certainembodiments, R^(P12) is a tetrahydropyranyl protecting group. In certainembodiments, R^(P12) is an alkoxyalkyl protecting group. In certainembodiments, R^(P12) is an ethoxyethyl protecting group.

In certain embodiments, R^(P13) is hydrogen. In certain embodiments,R^(P13) is substituted or unsubstitituted alkyl. In certain embodiments,R^(P13) is substituted or unsubstituted C₁₋₆ alkyl. In certainembodiments, R^(P13) is substituted or unsubstituted, branched C₁₋₆alkyl. In certain embodiments, R^(P13) is unsubstituted C₁₋₆ alkyl. Incertain embodiments, R^(P13) is methyl. In certain embodiments, R^(P13)is ethyl. In certain embodiments, R^(P13) is propyl. In certainembodiments, R^(P13) is iso-propyl. In certain embodiments, R^(P13) ist-butyl. In certain embodiments, R^(P13) is an oxygen protecting group.In certain embodiments, R^(P13) is a silyl protecting group. In certainembodiments, R^(P13) is a trialkyl silyl protecting group. In certainembodiments, R^(P13) is a t-butyldimethylsilyl protecting group. Incertain embodiments, R^(P13) is a trimethylsilyl protecting group. Incertain embodiments, R^(P13) is a triethylsilyl protecting group. Incertain embodiments, R^(P13) is a t-butyldiphenylsilyl protecting group.In certain embodiments, R^(P13) is a triisopropylsilyl protecting group.In certain embodiments, R^(P13) is a benzylic protecting group. Incertain embodiments, R^(P13) is a p-methoxybenzyl protecting group. Incertain embodiments, R^(P13) is an acyl protecting group. In certainembodiments, R^(P13) is an acetyl protecting group. In certainembodiments, R^(P13) is a benzoyl protecting group. In certainembodiments, R^(P13) is a p-nitro benzoyl protecting group. In certainembodiments, R^(P13) is a pivaloyl protecting group. In certainembodiments, R^(P13) is a t-butyl carbonate (BOC) protecting group. Incertain embodiments, R^(P13) is an acetal protecting group. In certainembodiments, R^(P13) is a tetrahydropyranyl protecting group. In certainembodiments, R^(P13) is an alkoxyalkyl protecting group. In certainembodiments, R^(P13) is an ethoxyethyl protecting group.

In certain embodiments, R^(P14) is hydrogen. In certain embodiments,R^(P14) is substituted or unsubstitituted alkyl. In certain embodiments,R^(P14) is substituted or unsubstituted C₁₋₆ alkyl. In certainembodiments, R^(P14) is substituted or unsubstituted, branched C₁₋₆alkyl. In certain embodiments, R^(P14) is unsubstituted C₁₋₆ alkyl. Incertain embodiments, R^(P14) is methyl. In certain embodiments, R^(P14)is ethyl. In certain embodiments, R^(P14) is propyl. In certainembodiments, R^(P14) is iso-propyl. In certain embodiments, R^(P14) ist-butyl. In certain embodiments, R^(P14) is an oxygen protecting group.In certain embodiments, R^(P14) is a silyl protecting group. In certainembodiments, R^(P14) is a trialkyl silyl protecting group. In certainembodiments, R^(P14) is a t-butyldimethylsilyl protecting group. Incertain embodiments, R^(P14) is a trimethylsilyl protecting group. Incertain embodiments, R^(P14) is a triethylsilyl protecting group. Incertain embodiments, R^(P14) is a t-butyldiphenylsilyl protecting group.In certain embodiments, R^(P14) is a triisopropylsilyl protecting group.In certain embodiments, R^(P14) is a benzylic protecting group. Incertain embodiments, R^(P14) is a p-methoxybenzyl protecting group. Incertain embodiments, R^(P14) is an acyl protecting group. In certainembodiments, R^(P14) is an acetyl protecting group. In certainembodiments, R^(P14) is a benzoyl protecting group. In certainembodiments, R^(P14) is a p-nitro benzoyl protecting group. In certainembodiments, R^(P14) is a pivaloyl protecting group. In certainembodiments, R^(P14) is a t-butyl carbonate (BOC) protecting group. Incertain embodiments, R^(P14) is an acetal protecting group. In certainembodiments, R^(P14) is a tetrahydropyranyl protecting group. In certainembodiments, R^(P14) is an alkoxyalkyl protecting group. In certainembodiments, R^(P14) is an ethoxyethyl protecting group.

In certain embodiments, R^(P15) is hydrogen. In certain embodiments,R^(P15) is substituted or unsubstitituted alkyl. In certain embodiments,R^(P15) is substituted or unsubstituted C₁₋₆ alkyl. In certainembodiments, R^(P15) is substituted or unsubstituted, branched C₁₋₆alkyl. In certain embodiments, R^(P15) is unsubstituted C₁₋₆ alkyl. Incertain embodiments, R^(P15) is methyl. In certain embodiments, R^(P15)is ethyl. In certain embodiments, R^(P15) is propyl. In certainembodiments, R^(P15) is iso-propyl. In certain embodiments, R^(P15) ist-butyl. In certain embodiments, R^(P15) is an oxygen protecting group.In certain embodiments, R^(P15) is a silyl protecting group. In certainembodiments, R^(P15) is a trialkyl silyl protecting group. In certainembodiments, R^(P15) is a t-butyldimethylsilyl protecting group. Incertain embodiments, R^(P15) is a trimethylsilyl protecting group. Incertain embodiments, R^(P15) is a triethylsilyl protecting group. Incertain embodiments, R^(P15) is a t-butyldiphenylsilyl protecting group.In certain embodiments, R^(P15) is a triisopropylsilyl protecting group.In certain embodiments, R^(P15) is a benzylic protecting group. Incertain embodiments, R^(P15) is a p-methoxybenzyl protecting group. Incertain embodiments, R^(P15) is an acyl protecting group. In certainembodiments, R^(P15) is an acetyl protecting group. In certainembodiments, R^(P15) is a benzoyl protecting group. In certainembodiments, R^(P15) is a p-nitro benzoyl protecting group. In certainembodiments, R^(P15) is a pivaloyl protecting group. In certainembodiments, R^(P15) is a t-butyl carbonate (BOC) protecting group. Incertain embodiments, R^(P15) is an acetal protecting group. In certainembodiments, R^(P15) is a tetrahydropyranyl protecting group. In certainembodiments, R^(P15) is an alkoxyalkyl protecting group. In certainembodiments, R^(P15) is an ethoxyethyl protecting group.

In certain embodiments, R^(P16) is hydrogen. In certain embodiments,R^(P16) is substituted or unsubstitituted alkyl. In certain embodiments,R^(P16) is substituted or unsubstituted C₁₋₆ alkyl. In certainembodiments, R^(P16) is substituted or unsubstituted, branched C₁₋₆alkyl. In certain embodiments, R^(P16) is unsubstituted C₁₋₆ alkyl. Incertain embodiments, R^(P16) is methyl. In certain embodiments, R^(P16)is ethyl. In certain embodiments, R^(P16) is propyl. In certainembodiments, R^(P16) is iso-propyl. In certain embodiments, R^(P16) ist-butyl. In certain embodiments, R^(P16) is an oxygen protecting group.In certain embodiments, R^(P16) is a silyl protecting group. In certainembodiments, R^(P16) is a trialkyl silyl protecting group. In certainembodiments, R^(P16) is a t-butyldimethylsilyl protecting group. Incertain embodiments, R^(P16) is a trimethylsilyl protecting group. Incertain embodiments, R^(P16) is a triethylsilyl protecting group. Incertain embodiments, R^(P16) is a t-butyldiphenylsilyl protecting group.In certain embodiments, R^(P16) is a triisopropylsilyl protecting group.In certain embodiments, R^(P16) is a benzylic protecting group. Incertain embodiments, R^(P16) is a p-methoxybenzyl protecting group. Incertain embodiments, R^(P16) is an acyl protecting group. In certainembodiments, R^(P16) is an acetyl protecting group. In certainembodiments, R^(P16) is a benzoyl protecting group. In certainembodiments, R^(P16) is a p-nitro benzoyl protecting group. In certainembodiments, R^(P16) is a pivaloyl protecting group. In certainembodiments, R^(P16) is a t-butyl carbonate (BOC) protecting group. Incertain embodiments, R^(P16) is an acetal protecting group. In certainembodiments, R^(P16) is a tetrahydropyranyl protecting group. In certainembodiments, R^(P16) is an alkoxyalkyl protecting group. In certainembodiments, R^(P16) is an ethoxyethyl protecting group.

In certain embodiments, R^(P17) is hydrogen. In certain embodiments,R^(P17) is substituted or unsubstitituted alkyl. In certain embodiments,R^(P17) is substituted or unsubstituted C₁₋₆ alkyl. In certainembodiments, R^(P17) is substituted or unsubstituted, branched C₁₋₆alkyl. In certain embodiments, R^(P17) is unsubstituted C₁₋₆ alkyl. Incertain embodiments, R^(P17) is methyl. In certain embodiments, R^(P17)is ethyl. In certain embodiments, R^(P17) is propyl. In certainembodiments, R^(P17) is iso-propyl. In certain embodiments, R^(P17) ist-butyl. In certain embodiments, R^(P17) is an oxygen protecting group.In certain embodiments, R^(P17) is a silyl protecting group. In certainembodiments, R^(P17) is a trialkyl silyl protecting group. In certainembodiments, R^(P17) is a t-butyldimethylsilyl protecting group. Incertain embodiments, R^(P17) is a trimethylsilyl protecting group. Incertain embodiments, R^(P17) is a triethylsilyl protecting group. Incertain embodiments, R^(P17) is a t-but protecting group. In certainembodiments, R^(P17) is a triisopropylsilyl protecting group. In certainembodiments, R^(P17) is a benzylic protecting group. In certainembodiments, R^(P17) is a p-methoxybenzyl protecting group. In certainembodiments, R^(P17) is an acyl protecting group. In certainembodiments, R^(P17) is an acetyl protecting group. In certainembodiments, R^(P17) is a benzoyl protecting group. In certainembodiments, R^(P17) is a p-nitro benzoyl protecting group. In certainembodiments, R^(P17) is a pivaloyl protecting group. In certainembodiments, R^(P17) is a t-butyl carbonate (BOC) protecting group. Incertain embodiments, R^(P17) is an acetal protecting group. In certainembodiments, R^(P17) is a tetrahydropyranyl protecting group. In certainembodiments, R^(P17) is an alkoxyalkyl protecting group. In certainembodiments, R^(P17) is an ethoxyethyl protecting group.

In certain embodiments, R^(P18) is hydrogen. In certain embodiments,R^(P18) is substituted or unsubstitituted alkyl. In certain embodiments,R^(P18) is substituted or unsubstituted C₁₋₆ alkyl. In certainembodiments, R^(P18) is substituted or unsubstituted, branched C₁₋₆alkyl. In certain embodiments, R^(P18) is unsubstituted C₁₋₆ alkyl. Incertain embodiments, R^(P18) is methyl. In certain embodiments, R^(P18)is ethyl. In certain embodiments, R^(P18) is propyl. In certainembodiments, R^(P18) is iso-propyl. In certain embodiments, R^(P18) ist-butyl. In certain embodiments, R^(P18) is an oxygen protecting group.In certain embodiments, R^(P18) is a silyl protecting group. In certainembodiments, R^(P18) is a trialkyl silyl protecting group. In certainembodiments, R^(P18) is a t-butyldimethylsilyl protecting group. Incertain embodiments, R^(P18) is a trimethylsilyl protecting group. Incertain embodiments, R^(P18) is a triethylsilyl protecting group. Incertain embodiments, R^(P18) is a t-butyldiphenylsilyl protecting group.In certain embodiments, R^(P18) is a triisopropylsilyl protecting group.In certain embodiments, R^(P18) is a benzylic protecting group. Incertain embodiments, R^(P18) is a p-methoxybenzyl protecting group. Incertain embodiments, R^(P18) is an acyl protecting group. In certainembodiments, R^(P18) is an acetyl protecting group. In certainembodiments, R^(P18) is a benzoyl protecting group. In certainembodiments, R^(P18) is a p-nitro benzoyl protecting group. In certainembodiments, R^(P18) is a pivaloyl protecting group. In certainembodiments, R^(P18) is a t-butyl carbonate (BOC) protecting group. Incertain embodiments, R^(P18) is an acetal protecting group. In certainembodiments, R^(P18) is a tetrahydropyranyl protecting group. In certainembodiments, R^(P18) is an alkoxyalkyl protecting group. In certainembodiments, R^(P18) is an ethoxyethyl protecting group.

In certain embodiments, R^(P19) is hydrogen. In certain embodiments,R^(P19) is substituted or unsubstitituted alkyl. In certain embodiments,R^(P19) is substituted or unsubstituted C₁₋₆ alkyl. In certainembodiments, R^(P19) is substituted or unsubstituted, branched C₁₋₆alkyl. In certain embodiments, R^(P19) is unsubstituted C₁₋₆ alkyl. Incertain embodiments, R^(P19) is methyl. In certain embodiments, R^(P19)is ethyl. In certain embodiments, R^(P19) is propyl. In certainembodiments, R^(P19) is iso-propyl. In certain embodiments, R^(P19) ist-butyl. In certain embodiments, R^(P19) is an oxygen protecting group.In certain embodiments, R^(P19) is a silyl protecting group. In certainembodiments, R^(P19) is a trialkyl silyl protecting group. In certainembodiments, R^(P19) is a t-butyldimethylsilyl protecting group. Incertain embodiments, R^(P19) is a trimethylsilyl protecting group. Incertain embodiments, R^(P19) is a triethylsilyl protecting group. Incertain embodiments, R^(P19) is a t-butyldiphenylsilyl protecting group.In certain embodiments, R^(P19) is a triisopropylsilyl protecting group.In certain embodiments, R^(P19) is a benzylic protecting group. Incertain embodiments, R^(P19) is a p-methoxybenzyl protecting group. Incertain embodiments, R^(P19) is an acyl protecting group. In certainembodiments, R^(P19) is an acetyl protecting group. In certainembodiments, R^(P19) is a benzoyl protecting group. In certainembodiments, R^(P19) is a p-nitro benzoyl protecting group. In certainembodiments, R^(P19) is a pivaloyl protecting group. In certainembodiments, R^(P19) is a t-butyl carbonate (BOC) protecting group. Incertain embodiments, R^(P19) is an acetal protecting group. In certainembodiments, R^(P19) is a tetrahydropyranyl protecting group. In certainembodiments, R^(P19) is an alkoxyalkyl protecting group. In certainembodiments, R^(P19) is an ethoxyethyl protecting group.

In certain embodiments, all of R^(P17), R^(P18), and R^(P19) areindependently a silyl protecting group. In certain embodiments, all ofR^(P17), R^(P18), and R^(P19) are a t-butyldimethylsilyl protectinggroup. In certain embodiments, R^(P4) is a silyl protecting group; andR^(P5) is an acyl protecting group. In certain embodiments, R^(P4) is at-butyldimethylsilyl protecting group; and R^(P5) is an acyl protectinggroup. In certain embodiments, R^(P4) is a silyl protecting group; andR^(P5) is an acetyl protecting group. In certain embodiments, R^(P4) isa t-butyldimethylsilyl protecting group; and R^(P5) is an acetylprotecting group. In certain embodiments, all of R^(P1), R^(P2), R^(P3),R^(P4), and R^(P7) are independently a silyl protecting group; andR^(P6) is a benzylic protecting group. In certain embodiments, all ofR^(P1), R^(P2), R^(P3), R^(P4), and R^(P7) are a t-butyldimethylsilylprotecting group; and R^(P6) is a benzylic protecting group. In certainembodiments, all of R^(P1), R^(P2), R^(P3), R^(P4), and R^(P7) areindependently a silyl protecting group; and R^(P6) is a p-methoxybenzylprotecting group. In certain embodiments, all of R^(P1), R^(P2), R^(P3),R^(P4), and R^(P7) are a t-butyldimethylsilyl protecting group; andR^(P6) is a p-methoxybenzyl protecting group. In certain embodiments,all of R^(P8), R^(P9), and R^(P11) are each independently a silylprotecting group; and R^(P10) is a benzylic protecting group. In certainembodiments, all of R^(P8), R^(P9), and R^(P11) are at-butyldimethylsilyl protecting group; and R^(P10) is a benzylicprotecting group. In certain embodiments, all of R^(P8), R^(P9), andR^(P11) are independently a silyl protecting group; and R^(P10) is ap-methoxybenzyl protecting group. In certain embodiments, all of R^(P8),R^(P9), and R^(P11) are a t-butyldimethylsilyl protecting group; andR^(P10) is a p-methoxybenzyl protecting group. In certain embodiments,all of R^(P12), R^(P13), R^(P14), and R^(P15) are independently a silylprotecting group; and R^(P16) is a benzylic protecting group. In certainembodiments, all of R^(P12), R^(P13), R^(P14), and R^(P15) are at-butyldimethylsilyl protecting group; and R^(P16) is a benzylicprotecting group. In certain embodiments, all of R^(P12)R^(P13),R^(P14), and R^(P15) are independently a silyl protecting group; andR^(P16) is a p-methoxybenzyl protecting group. In certain embodiments,all of R^(P12), R^(P13), R^(P14), and R^(P15) are a t-butyldimethylsilylprotecting group; and R^(P16) is a p-methoxybenzyl protecting group.

Groups R¹, R², R³, and R⁵

As generally described herein, R¹, R², R³, and R⁵ are each independentlyhydrogen, halogen, or substituted or unsubstituted alkyl.

In certain embodiments, R¹ is hydrogen. In certain embodiments, R¹ ishalogen (e.g., —F, —Cl, —Br, or —I). In certain embodiments, R¹ isfluorine. In certain embodiments, R¹ is chlorine. In certainembodiments, R¹ is substituted or unsubstitituted alkyl. In certainembodiments, R¹ is substituted or unsubstituted C₁₋₆ alkyl. In certainembodiments, R¹ is substituted or unsubstituted, branched C₁₋₆ alkyl. Incertain embodiments, R¹ is unsubstituted C₁₋₆ alkyl. In certainembodiments, R¹ is methyl. In certain embodiments, R¹ is methyl; and thecarbon to which the methyl group is attached is in the(S)-configuration. In certain embodiments, R¹ is methyl; and the carbonto which the methyl group is attached is in the (R)-configuration. Incertain embodiments, R¹ is ethyl. In certain embodiments, R¹ is propyl.In certain embodiments, R¹ is iso-propyl. In certain embodiments, R¹ isbutyl. In certain embodiments, R¹ is t-butyl.

In certain embodiments, the stereochemical configuration of the carbonatom to which R¹ is attached is (S). In certain embodiments, thestereochemical configuration of the carbon atom to which R¹ is attachedis (R).

In certain embodiments, R² is hydrogen. In certain embodiments, R² ishalogen (e.g., —F, —Cl, —Br, or —I). In certain embodiments, R² isfluorine. In certain embodiments, R² is chlorine. In certainembodiments, R² is substituted or unsubstitituted alkyl. In certainembodiments, R² is substituted or unsubstituted C₁₋₆ alkyl. In certainembodiments, R² is substituted or unsubstituted, branched C₁₋₆ alkyl. Incertain embodiments, R² is unsubstituted C₁₋₆ alkyl. In certainembodiments, R² is methyl. In certain embodiments, R² is methyl; and thecarbon to which the methyl group is attached is in the(S)-configuration. In certain embodiments, R² is methyl; and the carbonto which the methyl group is attached is in the (R)-configuration. Incertain embodiments, R² is ethyl. In certain embodiments, R² is propyl.In certain embodiments, R² is iso-propyl. In certain embodiments, R² isbutyl. In certain embodiments, R² is t-butyl.

In certain embodiments, the stereochemical configuration of the carbonatom to which R² is attached is (S). In certain embodiments, thestereochemical configuration of the carbon atom to which R² is attachedis (R).

In certain embodiments, R³ is hydrogen. In certain embodiments, R³ ishalogen (e.g., —F, —Cl, —Br, or —I). In certain embodiments, R³ isfluorine. In certain embodiments, R³ is chlorine. In certainembodiments, R³ is substituted or unsubstitituted alkyl. In certainembodiments, R³ is substituted or unsubstituted C₁₋₆ alkyl. In certainembodiments, R³ is substituted or unsubstituted, branched C₁₋₆ alkyl. Incertain embodiments, R³ is unsubstituted C₁₋₆ alkyl. In certainembodiments, R³ is methyl. In certain embodiments, R³ is methyl; and thecarbon to which the methyl group is attached is in the(S)-configuration. In certain embodiments, R³ is methyl; and the carbonto which the methyl group is attached is in the (R)-configuration. Incertain embodiments, R³ is ethyl. In certain embodiments, R³ is propyl.In certain embodiments, R³ is iso-propyl. In certain embodiments, R³ isbutyl. In certain embodiments, R³ is t-butyl.

In certain embodiments, the stereochemical configuration of the carbonatom to which R³ is attached is (S). In certain embodiments, thestereochemical configuration of the carbon atom to which R³ is attachedis (R).

In certain embodiments, R⁵ is hydrogen. In certain embodiments, R⁵ ishalogen (e.g., —F, —Cl, —Br, or —I). In certain embodiments, R⁵ isfluorine. In certain embodiments, R⁵ is chlorine. In certainembodiments, R⁵ is substituted or unsubstitituted alkyl. In certainembodiments, R⁵ is substituted or unsubstituted C₁₋₆ alkyl. In certainembodiments, R⁵ is substituted or unsubstituted, branched C₁₋₆ alkyl. Incertain embodiments, R⁵ is unsubstituted C₁₋₆ alkyl. In certainembodiments, R⁵ is methyl. In certain embodiments, R⁵ is methyl; and thecarbon to which the methyl group is attached is in the(S)-configuration. In certain embodiments, R⁵ is methyl; and the carbonto which the methyl group is attached is in the (R)-configuration. Incertain embodiments, R⁵ is ethyl. In certain embodiments, R⁵ is propyl.In certain embodiments, R⁵ is iso-propyl. In certain embodiments, R⁵ isbutyl. In certain embodiments, R⁵ is t-butyl.

In certain embodiments, the stereochemical configuration of the carbonatom to which R⁵ is attached is (S). In certain embodiments, thestereochemical configuration of the carbon atom to which R⁵ is attachedis (R).

In certain embodiments, all of R¹, R², R³, and R⁵ are independentlysubstituted or unsubstituted alkyl. In certain embodiments, all of R¹,R², R³, and R⁵ are independently substituted or unsubstituted C₁₋₆alkyl. In certain embodiments, all of R¹, R², R³, and R⁵ areindependently substituted or unsubstituted, branched C₁₋₆ alkyl. Incertain embodiments, all of R¹, R², R³, and R⁵ are independentlyunsubstituted C₁₋₆ alkyl. In certain embodiments, all of R¹, R², R³, andR⁵ are methyl. In certain embodiments, the stereochemical configurationof the carbon atom to which each of R¹, R², and R³ is attached is (S);and the stereochemical configuration of the carbon atom to which R⁵ isattached is (R). In certain embodiments, the stereochemicalconfiguration of the carbon atom to which each of R¹, R², and R³ isattached is (S); the stereochemical configuration of the carbon atom towhich R⁵ is attached is (R); and all of R¹, R², R³, and R³ are methyl.

Groups R⁴ and R⁶

As generally described herein, R⁴ and R⁶ are each independentlyhydrogen, halogen, or substituted or unsubstituted alkyl, or two R⁴groups can be taken together to form a

group. In certain embodiments, at least one R⁴ is hydrogen. In certainembodiments, both of R⁴ are hydrogen. In certain embodiments, at leastone R⁴ is halogen (e.g., —F, —Cl, —Br, or —I). In certain embodiments,at least one R⁴ is fluorine. In certain embodiments, at least one R⁴ ischlorine. In certain embodiments, at least one R⁴ is substituted orunsubstitituted alkyl. In certain embodiments, at least one R⁴ issubstituted or unsubstituted C₁₋₆ alkyl. In certain embodiments, atleast one R⁴ is substituted or unsubstituted, branched C₁₋₆ alkyl. Incertain embodiments, at least one R⁴ is unsubstituted C₁₋₆ alkyl. Incertain embodiments, at least one R⁴ is methyl. In certain embodiments,at least one R⁴ is methyl; and the carbon to which the methyl group isattached is in the (S)-configuration. In certain embodiments, at leastone R⁴ is methyl; and the carbon to which the methyl group is attachedis in the (R)-configuration. In certain embodiments, both of R⁴ aremethyl. In certain embodiments, at least one R⁴ is ethyl. In certainembodiments, at least one R⁴ is propyl. In certain embodiments, at leastone R⁴ is butyl. In certain embodiments, at least one R⁴ is t-butyl. Incertain embodiments, the stereochemical configuration of the carbon atomto which R⁴ is attached is (S). In certain embodiments, thestereochemical configuration of the carbon atom to which R⁴ is attachedis (R). In certain embodiments, two R⁴ groups are taken together to forma

group.

In certain embodiments, at least one R⁶ is hydrogen. In certainembodiments, both of R⁶ are hydrogen. In certain embodiments, at leastone R⁶ is halogen (e.g., —F, —Cl, —Br, or —I). In certain embodiments,at least one R⁶ is fluorine. In certain embodiments, at least one R⁶ ischlorine. In certain embodiments, at least one R⁶ is substituted orunsubstitituted alkyl. In certain embodiments, at least one R⁶ issubstituted or unsubstituted C₁₋₆ alkyl. In certain embodiments, atleast one R⁶ is substituted or unsubstituted, branched C₁₋₆ alkyl. Incertain embodiments, at least one R⁶ is unsubstituted C₁₋₆ alkyl. Incertain embodiments, at least one R⁶ is methyl. In certain embodiments,at least one R⁶ is methyl; and the carbon to which the methyl group isattached is in the (S)-configuration. In certain embodiments, at leastone R⁶ is methyl; and the carbon to which the methyl group is attachedis in the (R)-configuration. In certain embodiments, both of R⁶ aremethyl. In certain embodiments, at least one R⁶ is ethyl. In certainembodiments, at least one R⁶ is propyl. In certain embodiments, at leastone R⁶ is butyl. In certain embodiments, at least one R⁶ is t-butyl. Incertain embodiments, the stereochemical configuration of the carbon atomto which R⁶ is attached is (S). In certain embodiments, thestereochemical configuration of the carbon atom to which R⁶ is attachedis (R). In certain embodiments, two R⁶ groups are taken together to forma

group.

In certain embodiments, two R⁴ groups are taken together to form a

group; and two R⁶ groups are taken together to form a

group.Groups R^(X), R^(Y), R^(X1), R^(Y1), and R^(XY)

As generally described herein, R^(X) is —OR^(X1), wherein R^(X1) ishydrogen, substituted or unsubstituted alkyl, or an oxygen protectinggroup; R^(Y) is —OR^(Y1), wherein R^(Y1) is hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group; and R^(X) and R^(Y)can be taken with their intervening atoms to form a substituted orunsubstituted heterocyclic ring.

In certain embodiments, the stereochemical configuration of the carbonatom to which R^(X) is attached is (S). In certain embodiments, thestereochemical configuration of the carbon atom to which R^(X) isattached is (R).

In certain embodiments, the stereochemical configuration of R^(Y) is(S). In certain embodiments, the stereochemical configuration of R^(Y)is (R).

In certain embodiments, R^(X1) is hydrogen. In certain embodiments,R^(X1) is substituted or unsubstitituted alkyl. In certain embodiments,R^(X1) is substituted or unsubstituted C₁₋₆ alkyl. In certainembodiments, R^(X1) is substituted or unsubstituted, branched C₁₋₆alkyl. In certain embodiments, R^(X1) is unsubstituted C₁₋₆ alkyl. Incertain embodiments, R^(X1) is methyl. In certain embodiments, R^(X1) isethyl. In certain embodiments, R^(X1) is propyl. In certain embodiments,R^(X1) is iso-propyl. In certain embodiments, R^(X1) is t-butyl. Incertain embodiments, R^(X1) is an oxygen protecting group. In certainembodiments, R^(X1) is a silyl protecting group. In certain embodiments,R^(X1) is a trialkyl silyl protecting group. In certain embodiments,R^(X1) is a t-butyldimethylsilyl protecting group. In certainembodiments, R^(X1) is a trimethylsilyl protecting group. In certainembodiments, R^(X1) is a triethylsilyl protecting group. In certainembodiments, R^(X1) is a t-butyldiphenylsilyl protecting group. Incertain embodiments, R^(X1) is a triisopropylsilyl protecting group. Incertain embodiments, R^(X1) is a benzylic protecting group. In certainembodiments, R^(X1) is a p-methoxybenzyl protecting group. In certainembodiments, R^(X1) is an acyl protecting group. In certain embodiments,R^(X1) is an acetyl protecting group. In certain embodiments, R^(X1) isa benzoyl protecting group. In certain embodiments, R^(X1) is a p-nitrobenzoyl protecting group. In certain embodiments, R^(X1) is a pivaloylprotecting group. In certain embodiments, R^(X1) is a t-butyl carbonate(BOC) protecting group. In certain embodiments, R^(X1) is an acetalprotecting group. In certain embodiments, R^(X1) is a tetrahydropyranylprotecting group. In certain embodiments, R^(X1) is an alkoxyalkylprotecting group. In certain embodiments, R^(X1) is an ethoxyethylprotecting group.

In certain embodiments, R^(Y1) is hydrogen. In certain embodiments,R^(Y1) is substituted or unsubstitituted alkyl. In certain embodiments,R^(Y1) is substituted or unsubstituted C₁₋₆ alkyl. In certainembodiments, R^(Y1) is substituted or unsubstituted, branched C₁₋₆alkyl. In certain embodiments, R^(Y1) is unsubstituted C₁₋₆ alkyl. Incertain embodiments, R^(Y1) is methyl. In certain embodiments, R^(Y1) isethyl. In certain embodiments, R^(Y1) is propyl. In certain embodiments,R^(Y1) is iso-propyl. In certain embodiments, R^(Y1) is t-butyl. Incertain embodiments, R^(Y1) is an oxygen protecting group. In certainembodiments, R^(Y1) is a silyl protecting group. In certain embodiments,R^(Y1) is a trialkyl silyl protecting group. In certain embodiments,R^(Y1) is a t-butyldimethylsilyl protecting group. In certainembodiments, R^(Y1) is a trimethylsilyl protecting group. In certainembodiments, R^(Y1) is a triethylsilyl protecting group. In certainembodiments, R^(Y1) is a t-butyldiphenylsilyl protecting group. Incertain embodiments, R^(Y1) is a triisopropylsilyl protecting group. Incertain embodiments, R^(Y1) is a benzylic protecting group. In certainembodiments, R^(Y1) is a p-methoxybenzyl protecting group. In certainembodiments, R^(Y1) is an acyl protecting group. In certain embodiments,R^(Y1) is an acetyl protecting group. In certain embodiments, R^(Y1) isa benzoyl protecting group. In certain embodiments, R^(Y1) is a p-nitrobenzoyl protecting group. In certain embodiments, R^(Y1) is a pivaloylprotecting group. In certain embodiments, R^(Y1) is a t-butyl carbonate(BOC) protecting group. In certain embodiments, R^(Y1) is an acetalprotecting group. In certain embodiments, R^(Y1) is a tetrahydropyranylprotecting group. In certain embodiments, R^(Y1) is an alkoxyalkylprotecting group. In certain embodiments, R^(Y1) is an ethoxyethylprotecting group.

In certain embodiments, both R^(X1) and R^(Y1) are hydrogen.

In certain embodiments, the stereochemical configuration of the carbonatom to which R^(X) is attached is (S). In certain embodiments, thestereochemical configuration of the carbon atom to which R^(X) isattached is (R). In certain embodiments, the stereochemicalconfiguration of the carbon atom to which R^(Y) is attached is (S). Incertain embodiments, the stereochemical configuration of the carbon atomto which R^(Y) is attached is (R).

In certain embodiments, the stereochemical configuration of the carbonatom to which R^(X) is attached is (S); and the stereochemicalconfiguration of the carbon atom to which R^(Y) is attached is (S). Incertain embodiments, the stereochemical configuration of the carbon atomto which R^(X) is attached is (R); and the stereochemical configurationof the carbon atom to which R^(Y) is attached is (R). In certainembodiments, the stereochemical configuration of the carbon atom towhich R^(X) is attached is (S); and the stereochemical configuration ofthe carbon atom to which R^(Y) is attached is (R). In certainembodiments, the stereochemical configuration of the carbon atom towhich R^(X) is attached is (R); and the stereochemical configuration ofthe carbon atom to which R^(Y) is attached is (S).

In certain embodiments, R^(X) and R^(Y) are taken with their interveningatoms to form a substituted or unsubstituted heterocyclic ring. Incertain embodiments, R^(X) and R^(Y) form a substituted orunsubstituted, 5-membered heterocyclic ring. In certain embodiments,R^(X) and R^(Y) form a substituted or unsubstituted, 6-memberedheterocyclic ring. In certain embodiments, R^(X) and R^(Y) form asubstituted or unsubstituted dioxolane. In certain embodiments, R^(X)and R^(Y) form a mono-substituted dioxolane. In certain embodiments,R^(X) and R^(Y) form a dioxolane substituted with one instance of asubstituted or unsubstituted phenyl ring. In certain embodiments, R^(X)and R^(Y) form a dioxolane substituted with one instance of amono-substituted phenyl ring. In certain embodiments, R^(X) and R^(Y)form a substituted or unsubstituted dioxane.

In certain embodiments, R^(X) and R^(Y) form a dioxolane ringsubstituted with one instance of R^(XY) of formula. For example, in acompound of Formula (I), when R^(X) and R^(Y) form a dioxolane ringsubstituted with one instance of R^(XY), provided is a compound ofFormula (I-a):

In certain embodiments, R^(X) and R^(Y) form

wherein R^(XY) is a substituted or unsubstituted aryl ring. In certainembodiments, R^(X) and R^(Y) form

wherein R^(XY) is a substituted or unsubstituted aryl ring. In certainembodiments, R^(X) and R^(Y) form

wherein R^(XY) is a substituted or unsubstituted aryl ring. In certainembodiments, R^(X) and R^(Y) form

wherein R^(XY) is a substituted or unsubstituted aryl ring. In certainembodiments, R^(X) and R^(Y) form

wherein R^(XY) is a substituted or unsubstituted aryl ring. In certainembodiments, R^(X) and R^(Y) form

wherein R^(XY) is a substituted or unsubstituted aryl ring. In certainembodiments, R^(X) and R^(Y) form

wherein R^(XY) is a substituted or unsubstituted aryl ring. In certainembodiments, R^(X) and R^(Y) form

wherein R^(XY) is a substituted or unsubstituted aryl ring. In certainembodiments, R^(XY) is monosubstituted phenyl. In certain embodiments,R^(XY) is p-methoxyphenyl. In certain embodiments, R^(XY) isdisubstituted phenyl.

Group R⁷

In certain embodiments, R⁷ is hydrogen. In certain embodiments, R⁷ issubstituted or unsubstitituted alkyl. In certain embodiments, R⁷ issubstituted or unsubstituted C₁₋₆ alkyl. In certain embodiments, R⁷ issubstituted or unsubstituted, branched C₁₋₆ alkyl. In certainembodiments, R⁷ is unsubstituted C₁₋₆ alkyl. In certain embodiments, R⁷is methyl. In certain embodiments, R⁷ is ethyl. In certain embodiments,R⁷ is propyl. In certain embodiments, R⁷ is iso-propyl. In certainembodiments, R⁷ is t-butyl. In certain embodiments, R⁷ is an oxygenprotecting group. In certain embodiments, R⁷ is a silyl protectinggroup. In certain embodiments, R⁷ is a trialkyl silyl protecting group.In certain embodiments, R⁷ is a t-butyldimethylsilyl protecting group.In certain embodiments, R⁷ is a trimethylsilyl protecting group. Incertain embodiments, R⁷ is a triethylsilyl protecting group. In certainembodiments, R⁷ is a t-butyldiphenylsilyl protecting group. In certainembodiments, R⁷ is a triisopropylsilyl protecting group. In certainembodiments, R⁷ is a benzylic protecting group. In certain embodiments,R⁷ is a p-methoxybenzyl protecting group. In certain embodiments, R⁷ isan acyl protecting group. In certain embodiments, R⁷ is an acetylprotecting group. In certain embodiments, R⁷ is a benzoyl protectinggroup. In certain embodiments, R⁷ is a p-nitro benzoyl protecting group.In certain embodiments, R⁷ is a pivaloyl protecting group. In certainembodiments, R⁷ is a t-butyl carbonate (BOC) protecting group. Incertain embodiments, R⁷ is an acetal protecting group. In certainembodiments, R⁷ is a tetrahydropyranyl protecting group. In certainembodiments, R⁷ is an alkoxyalkyl protecting group. In certainembodiments, R⁷ is an ethoxyethyl protecting group.

Pharmaceutical Compositions and Administration

The present invention provides pharmaceutical compositions comprising ahalichondrin A, norhalichondrin A, or homohalichondrin A analog of thepresent invention, or a pharmaceutically acceptable salt thereof, asdescribed herein, and optionally a pharmaceutically acceptableexcipient.

The present disclosure provides pharmaceutical compositions comprising ahalichondrin A, norhalichondrin A, or homohalichondrin A analogdescribed herein, e.g., a compound of Formula (I)-(III), or apharmaceutically acceptable salt thereof, as described herein, andoptionally a pharmaceutically acceptable excipient. It will beunderstood by one of ordinary skill in the art that the halichondrin A,norhalichondrin A, or homohalichondrin A analogs described herein, orsalts thereof, may be present in various forms, such as amorphous forms,hydrates, solvates, or polymorphic forms. In certain embodiments, aprovided composition comprises two or more compounds described herein.In certain embodiments, a halichondrin A, norhalichondrin A, orhomohalichondrin A analog described herein, or a pharmaceuticallyacceptable salt thereof, is provided in an effective amount in thepharmaceutical composition. In certain embodiments, the effective amountis a therapeutically effective amount. In certain embodiments, theeffective amount is an amount effective for treating or preventing acondition associated with aberrant cell proliferation. In certainembodiments, the effective amount is an amount effective for treating orpreventing cancer. In certain embodiments, the effective amount is anamount effective for treating or preventing metastatic breast cancer. Incertain embodiments, the effective amount is an amount effective fortreating or preventing non-small cell lung cancer. In certainembodiments, the effective amount is an amount effective for treating orpreventing prostate cancer. In certain embodiments, the effective amountis an amount effective for treating or preventing a sarcoma. In certainembodiments, the effective amount is an amount effective for inhibitingmitosis in a cancer cell in a subject. In certain embodiments, theeffective amount is an amount effective for inducing apoptosis in acancer cell in a subject. In certain embodiments, the effective amountis an amount effective for binding to microtubules in a cancer cell in asubject. In certain embodiments, the effective amount is an amounteffective for inhibiting microtubule dynamics in a cancer cell in asubject.

Pharmaceutically acceptable excipients include any and all solvents,diluents, or other liquid vehicles, dispersions, suspension aids,surface active agents, isotonic agents, thickening or emulsifyingagents, preservatives, solid binders, lubricants, and the like, assuited to the particular dosage form desired. General considerations informulation and/or manufacture of pharmaceutical compositions agents canbe found, for example, in Remington's Pharmaceutical Sciences, SixteenthEdition, E. W. Martin (Mack Publishing Co., Easton, Pa., 1980), andRemington: The Science and Practice of Pharmacy, 21st Edition(Lippincott Williams & Wilkins, 2005).

Pharmaceutical compositions described herein can be prepared by anymethod known in the art of pharmacology. In general, such preparatorymethods include the steps of bringing the halichondrin A,norhalichondrin A, or homohalichondrin A analog of the present inventioninto association with a carrier and/or one or more other accessoryingredients, and then, if necessary and/or desirable, shaping and/orpackaging the product into a desired single- or multi-dose unit.

Pharmaceutical compositions can be prepared, packaged, and/or sold inbulk, as a single unit dose, and/or as a plurality of single unit doses.As used herein, a “unit dose” is discrete amount of the pharmaceuticalcomposition comprising a predetermined amount of the halichondrin A,norhalichondrin A, or homohalichondrin A analog of the presentinvention. The amount of the halichondrin A, norhalichondrin A, orhomohalichondrin A analog is generally equal to the dosage of thehalichondrin A, norhalichondrin A, or homohalichondrin A analog whichwould be administered to a subject and/or a convenient fraction of sucha dosage, such as, for example, one-half or one-third of such a dosage.

Relative amounts of the halichondrin A, norhalichondrin A, orhomohalichondrin A analog, the pharmaceutically acceptable excipient,and/or any additional ingredients in a pharmaceutical composition of theinvention will vary, depending upon the identity, size, and/or conditionof the subject treated and further depending upon the route by which thecomposition is to be administered. By way of example, the compositionmay comprise between 0.1% and 100% (w/w) of the halichondrin A,norhalichondrin A, or homohalichondrin A analog.

Pharmaceutically acceptable excipients used in the manufacture ofprovided pharmaceutical compositions include inert diluents, dispersingand/or granulating agents, surface active agents and/or emulsifiers,disintegrating agents, binding agents, preservatives, buffering agents,lubricating agents, and/or oils. Excipients such as cocoa butter andsuppository waxes, coloring agents, coating agents, sweetening,flavoring, and perfuming agents may also be present in the composition.

Exemplary diluents include calcium carbonate, sodium carbonate, calciumphosphate, dicalcium phosphate, calcium sulfate, calcium hydrogenphosphate, sodium phosphate lactose, sucrose, cellulose,microcrystalline cellulose, kaolin, mannitol, sorbitol, inositol, sodiumchloride, dry starch, cornstarch, powdered sugar, and mixtures thereof.

Exemplary granulating and/or dispersing agents include potato starch,corn starch, tapioca starch, sodium starch glycolate, clays, alginicacid, guar gum, citrus pulp, agar, bentonite, cellulose and woodproducts, natural sponge, cation-exchange resins, calcium carbonate,silicates, sodium carbonate, cross-linked poly(vinyl-pyrrolidone)(crospovidone), sodium carboxymethyl starch (sodium starch glycolate),carboxymethyl cellulose, cross-linked sodium carboxymethyl cellulose(croscarmellose), methylcellulose, pregelatinized starch (starch 1500),microcrystalline starch, water insoluble starch, calcium carboxymethylcellulose, magnesium aluminum silicate (Veegum), sodium lauryl sulfate,quaternary ammonium compounds, and mixtures thereof.

Exemplary surface active agents and/or emulsifiers include naturalemulsifiers (e.g., acacia, agar, alginic acid, sodium alginate,tragacanth, chondrux, cholesterol, xanthan, pectin, gelatin, egg yolk,casein, wool fat, cholesterol, wax, and lecithin), colloidal clays(e.g.,bentonite (aluminum silicate) and Veegum (magnesium aluminumsilicate), long chain amino acid derivatives, high molecular weightalcohols (e.g., stearyl alcohol, cetyl alcohol, oleyl alcohol, triacetinmonostearate, ethylene glycol distearate, glyceryl monostearate, andpropylene glycol monostearate, polyvinyl alcohol), carbomers (e.g.,carboxy polymethylene, polyacrylic acid, acrylic acid polymer, andcarboxyvinyl polymer), carrageenan, cellulosic derivatives(e.g.,carboxymethylcellulose sodium, powdered cellulose, hydroxymethylcellulose, hydroxypropyl cellulose, hydroxypropyl methylcellulose,methylcellulose), sorbitan fatty acid esters (e.g.,polyoxyethylenesorbitan monolaurate (Tween 20), polyoxyethylene sorbitan (Tween 60),polyoxyethylene sorbitan monooleate (Tween 80), sorbitan monopalmitate(Span 40), sorbitan monostearate (Span 60), sorbitan tristearate (Span65), glyceryl monooleate, sorbitan monooleate (Span 80), polyoxyethyleneesters (e.g.,polyoxyethylene monostearate (Myrj 45), polyoxyethylenehydrogenated castor oil, polyethoxylated castor oil, polyoxymethylenestearate, and Solutol), sucrose fatty acid esters, polyethylene glycolfatty acid esters (e.g.,Cremophor), polyoxyethylene ethers,(e.g.,polyoxyethylene lauryl ether (Brij 30), poly(vinyl-pyrrolidone),diethylene glycol monolaurate, triethanolamine oleate, sodium oleate,potassium oleate, ethyl oleate, oleic acid, ethyl laurate, sodium laurylsulfate, Pluronic F68, Poloxamer 188, cetrimonium bromide,cetylpyridinium chloride, benzalkonium chloride, docusate sodium, and/ormixtures thereof.

Exemplary binding agents include starch (e.g.,cornstarch and starchpaste), gelatin, sugars (e.g., sucrose, glucose, dextrose, dextrin,molasses, lactose, lactitol, mannitol, etc.), natural and synthetic gums(e.g., acacia, sodium alginate, extract of Irish moss, panwar gum,ghatti gum, mucilage of isapol husks, carboxymethylcellulose,methylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropyl methylcellulose, microcrystalline cellulose,cellulose acetate, poly(vinyl-pyrrolidone), magnesium aluminum silicate(Veegum), and larch arabogalactan), alginates, polyethylene oxide,polyethylene glycol, inorganic calcium salts, silicic acid,polymethacrylates, waxes, water, alcohol, and/or mixtures thereof.

Exemplary preservatives include antioxidants, chelating agents,antimicrobial preservatives, antifungal preservatives, alcoholpreservatives, acidic preservatives, and other preservatives.

Exemplary antioxidants include alpha tocopherol, ascorbic acid, acorbylpalmitate, butylated hydroxyanisole, butylated hydroxytoluene,monothioglycerol, potassium metabisulfite, propionic acid, propylgallate, sodium ascorbate, sodium bisulfite, sodium metabisulfite, andsodium sulfite.

Exemplary chelating agents include ethylenediaminetetraacetic acid(EDTA) and salts and hydrates thereof (e.g., sodium edetate, disodiumedetate, trisodium edetate, calcium disodium edetate, dipotassiumedetate, and the like), citric acid and salts and hydrates thereof(e.g., citric acid monohydrate), fumaric acid and salts and hydratesthereof, malic acid and salts and hydrates thereof, phosphoric acid andsalts and hydrates thereof, and tartaric acid and salts and hydratesthereof. Exemplary antimicrobial preservatives include benzalkoniumchloride, benzethonium chloride, benzyl alcohol, bronopol, cetrimide,cetylpyridinium chloride, chlorhexidine, chlorobutanol, chlorocresol,chloroxylenol, cresol, ethyl alcohol, glycerin, hexetidine, imidurea,phenol, phenoxyethanol, phenylethyl alcohol, phenylmercuric nitrate,propylene glycol, and thimerosal.

Exemplary antifungal preservatives include butyl paraben, methylparaben, ethyl paraben, propyl paraben, benzoic acid, hydroxybenzoicacid, potassium benzoate, potassium sorbate, sodium benzoate, sodiumpropionate, and sorbic acid.

Exemplary alcohol preservatives include ethanol, polyethylene glycol,phenol, phenolic compounds, bisphenol, chlorobutanol, hydroxybenzoate,and phenylethyl alcohol.

Exemplary acidic preservatives include vitamin A, vitamin C, vitamin E,beta-carotene, citric acid, acetic acid, dehydroacetic acid, ascorbicacid, sorbic acid, and phytic acid.

Other preservatives include tocopherol, tocopherol acetate, deteroximemesylate, cetrimide, butylated hydroxyanisol (BHA), butylatedhydroxytoluene (BHT), ethylenediamine, sodium lauryl sulfate (SLS),sodium lauryl ether sulfate (SLES), sodium bisulfite, sodiummetabisulfite, potassium sulfite, potassium metabisulfite, Glydant Plus,Phenonip, methylparaben, Germall 115, Germaben II, Neolone, Kathon, andEuxyl. In certain embodiments, the preservative is an anti-oxidant. Inother embodiments, the preservative is a chelating agent.

Exemplary buffering agents include citrate buffer solutions, acetatebuffer solutions, phosphate buffer solutions, ammonium chloride, calciumcarbonate, calcium chloride, calcium citrate, calcium glubionate,calcium gluceptate, calcium gluconate, D-gluconic acid, calciumglycerophosphate, calcium lactate, propanoic acid, calcium levulinate,pentanoic acid, dibasic calcium phosphate, phosphoric acid, tribasiccalcium phosphate, calcium hydroxide phosphate, potassium acetate,potassium chloride, potassium gluconate, potassium mixtures, dibasicpotassium phosphate, monobasic potassium phosphate, potassium phosphatemixtures, sodium acetate, sodium bicarbonate, sodium chloride, sodiumcitrate, sodium lactate, dibasic sodium phosphate, monobasic sodiumphosphate, sodium phosphate mixtures, tromethamine, magnesium hydroxide,aluminum hydroxide, alginic acid, pyrogen-free water, isotonic saline,Ringer's solution, ethyl alcohol, and mixtures thereof.

Exemplary lubricating agents include magnesium stearate, calciumstearate, stearic acid, silica, talc, malt, glyceryl behanate,hydrogenated vegetable oils, polyethylene glycol, sodium benzoate,sodium acetate, sodium chloride, leucine, magnesium lauryl sulfate,sodium lauryl sulfate, and mixtures thereof.

Exemplary natural oils include almond, apricot kernel, avocado, babassu,bergamot, black current seed, borage, cade, camomile, canola, caraway,carnauba, castor, cinnamon, cocoa butter, coconut, cod liver, coffee,corn, cotton seed, emu, eucalyptus, evening primrose, fish, flaxseed,geraniol, gourd, grape seed, hazel nut, hyssop, isopropyl myristate,jojoba, kukui nut, lavandin, lavender, lemon, litsea cubeba, macademianut, mallow, mango seed, meadowfoam seed, mink, nutmeg, olive, orange,orange roughy, palm, palm kernel, peach kernel, peanut, poppy seed,pumpkin seed, rapeseed, rice bran, rosemary, safflower, sandalwood,sasquana, savoury, sea buckthorn, sesame, shea butter, silicone,soybean, sunflower, tea tree, thistle, tsubaki, vetiver, walnut, andwheat germ oils. Exemplary synthetic oils include, but are not limitedto, butyl stearate, caprylic triglyceride, capric triglyceride,cyclomethicone, diethyl sebacate, dimethicone 360, isopropyl myristate,mineral oil, octyldodecanol, oleyl alcohol, silicone oil, and mixturesthereof.

Liquid dosage forms for oral and parenteral administration includepharmaceutically acceptable emulsions, microemulsions, solutions,suspensions, syrups and elixirs. In addition to the halichondrin A,norhalichondrin A, or homohalichondrin A analogs, the liquid dosageforms may comprise inert diluents commonly used in the art such as, forexample, water or other solvents, solubilizing agents and emulsifierssuch as ethyl alcohol, isopropyl alcohol, ethyl carbonate, ethylacetate, benzyl alcohol, benzyl benzoate, propylene glycol, 1,3-butyleneglycol, dimethylformamide, oils (e.g., cottonseed, groundnut, corn,germ, olive, castor, and sesame oils), glycerol, tetrahydrofurfurylalcohol, polyethylene glycols and fatty acid esters of sorbitan, andmixtures thereof. Besides inert diluents, the oral compositions caninclude adjuvants such as wetting agents, emulsifying and suspendingagents, sweetening, flavoring, and perfuming agents. In certainembodiments for parenteral administration, the conjugates of theinvention are mixed with solubilizing agents such as Cremophor,alcohols, oils, modified oils, glycols, polysorbates, cyclodextrins,polymers, and mixtures thereof.

Injectable preparations, for example, sterile injectable aqueous oroleaginous suspensions can be formulated according to the known artusing suitable dispersing or wetting agents and suspending agents. Thesterile injectable preparation can be a sterile injectable solution,suspension or emulsion in a nontoxic parenterally acceptable diluent orsolvent, for example, as a solution in 1,3-butanediol. Among theacceptable vehicles and solvents that can be employed are water,Ringer's solution, U.S.P. and isotonic sodium chloride solution. Inaddition, sterile, fixed oils are conventionally employed as a solventor suspending medium. For this purpose any bland fixed oil can beemployed including synthetic mono- or diglycerides. In addition, fattyacids such as oleic acid are used in the preparation of injectables.

The injectable formulations can be sterilized, for example, byfiltration through a bacterial-retaining filter, or by incorporatingsterilizing agents in the form of sterile solid compositions which canbe dissolved or dispersed in sterile water or other sterile injectablemedium prior to use.

In order to prolong the effect of a drug, it is often desirable to slowthe absorption of the drug from subcutaneous or intramuscular injection.This can be accomplished by the use of a liquid suspension ofcrystalline or amorphous material with poor water solubility. The rateof absorption of the drug then depends upon its rate of dissolutionwhich, in turn, may depend upon crystal size and crystalline form.Alternatively, delayed absorption of a parenterally administered drugform is accomplished by dissolving or suspending the drug in an oilvehicle.

Compositions for rectal or vaginal administration are typicallysuppositories which can be prepared by mixing the compounds of theinvention with suitable non-irritating excipients or carriers such ascocoa butter, polyethylene glycol, or a suppository wax which are solidat ambient temperature but liquid at body temperature and therefore meltin the rectum or vaginal cavity and release the halichondrin A,norhalichondrin A, or homohalichondrin A analog.

Solid dosage forms for oral administration include capsules, tablets,pills, powders, and granules. In such solid dosage forms, thehalichondrin A, norhalichondrin A, or homohalichondrin A analog is mixedwith at least one inert, pharmaceutically acceptable excipient orcarrier such as sodium citrate or dicalcium phosphate and/or a) fillersor extenders such as starches, lactose, sucrose, glucose, mannitol, andsilicic acid, b) binders such as, for example, carboxymethylcellulose,alginates, gelatin, polyvinylpyrrolidinone, sucrose, and acacia, c)humectants such as glycerol, d) disintegrating agents such as agar,calcium carbonate, potato or tapioca starch, alginic acid, certainsilicates, and sodium carbonate, e) solution retarding agents such asparaffin, f) absorption accelerators such as quaternary ammoniumcompounds, g) wetting agents such as, for example, cetyl alcohol andglycerol monostearate, h) absorbents such as kaolin and bentonite clay,and i) lubricants such as talc, calcium stearate, magnesium stearate,solid polyethylene glycols, sodium lauryl sulfate, and mixtures thereof.In the case of capsules, tablets and pills, the dosage form may comprisebuffering agents.

Solid compositions of a similar type can be employed as fillers in softand hard-filled gelatin capsules using such excipients as lactose ormilk sugar as well as high molecular weight polyethylene glycols and thelike. The solid dosage forms of tablets, dragees, capsules, pills, andgranules can be prepared with coatings and shells such as entericcoatings and other coatings well known in the pharmaceutical Formulatingart. They may optionally comprise opacifying agents and can be of acomposition that they release the halichondrin A, norhalichondrin A, orhomohalichondrin A analog (s) only, or preferentially, in a certain partof the intestinal tract, optionally, in a delayed manner. Examples ofembedding compositions which can be used include polymeric substancesand waxes. Solid compositions of a similar type can be employed asfillers in soft and hard-filled gelatin capsules using such excipientsas lactose or milk sugar as well as high molecular weight polethyleneglycols and the like.

The halichondrin A, norhalichondrin A, or homohalichondrin A analog canbe in micro-encapsulated form with one or more excipients as notedabove. The solid dosage forms of tablets, dragees, capsules, pills, andgranules can be prepared with coatings and shells such as entericcoatings, release controlling coatings and other coatings well known inthe pharmaceutical formulating art. In such solid dosage forms thehalichondrin A, norhalichondrin A, or homohalichondrin A analog can beadmixed with at least one inert diluent such as sucrose, lactose orstarch. Such dosage forms may comprise, as is normal practice,additional substances other than inert diluents, e.g., tabletinglubricants and other tableting aids such a magnesium stearate andmicrocrystalline cellulose. In the case of capsules, tablets and pills,the dosage forms may comprise buffering agents. They may optionallycomprise opacifying agents and can be of a composition that they releasethe halichondrin A, norhalichondrin A, or homohalichondrin A analog (s)only, or preferentially, in a certain part of the intestinal tract,optionally, in a delayed manner. Examples of embedding compositionswhich can be used include polymeric substances and waxes.

Dosage forms for topical and/or transdermal administration of ahalichondrin A, norhalichondrin A, or homohalichondrin A analog of thisinvention may include ointments, pastes, creams, lotions, gels, powders,solutions, sprays, inhalants and/or patches. Generally, the halichondrinA, norhalichondrin A, or homohalichondrin A analog is admixed understerile conditions with a pharmaceutically acceptable carrier and/or anyneeded preservatives and/or buffers as can be required. Additionally,the present invention contemplates the use of transdermal patches, whichoften have the added advantage of providing controlled delivery of ahalichondrin A, norhalichondrin A, or homohalichondrin A analog to thebody. Such dosage forms can be prepared, for example, by dissolvingand/or dispensing the halichondrin A, norhalichondrin A, orhomohalichondrin A analog in the proper medium. Alternatively oradditionally, the rate can be controlled by either providing a ratecontrolling membrane and/or by dispersing the halichondrin A,norhalichondrin A, or homohalichondrin A analog in a polymer matrixand/or gel.

Suitable devices for use in delivering intradermal pharmaceuticalcompositions described herein include short needle devices. Intradermalcompositions can be administered by devices which limit the effectivepenetration length of a needle into the skin. Jet injection deviceswhich deliver liquid vaccines to the dermis via a liquid jet injectorand/or via a needle which pierces the stratum corneum and produces a jetwhich reaches the dermis are suitable. Ballistic powder/particledelivery devices which use compressed gas to accelerate vaccine inpowder form through the outer layers of the skin to the dermis aresuitable. Alternatively or additionally, conventional syringes can beused in the classical mantoux method of intradermal administration.

Formulations suitable for topical administration include, but are notlimited to, liquid and/or semi liquid preparations such as liniments,lotions, oil in water and/or water in oil emulsions such as creams,ointments and/or pastes, and/or solutions and/or suspensions.Topically-administrable formulations may, for example, comprise fromabout 1% to about 10% (w/w) halichondrin A, norhalichondrin A, orhomohalichondrin A analog, although the concentration of thehalichondrin A, norhalichondrin A, or homohalichondrin A analog can beas high as the solubility limit of the halichondrin A, norhalichondrinA, or homohalichondrin A analog in the solvent. Formulations for topicaladministration may further comprise one or more of the additionalingredients described herein.

A pharmaceutical composition of the invention can be prepared, packaged,and/or sold in a formulation suitable for pulmonary administration viathe buccal cavity. Such a formulation may comprise dry particles whichcomprise the halichondrin A, norhalichondrin A, or homohalichondrin Aanalog and which have a diameter in the range from about 0.5 to about 7nanometers or from about 1 to about 6 nanometers. Such compositions areconveniently in the form of dry powders for administration using adevice comprising a dry powder reservoir to which a stream of propellantcan be directed to disperse the powder and/or using a self propellingsolvent/powder dispensing container such as a device comprising thehalichondrin A, norhalichondrin A, or homohalichondrin A analogdissolved and/or suspended in a low-boiling propellant in a sealedcontainer. Such powders comprise particles wherein at least 98% of theparticles by weight have a diameter greater than 0.5 nanometers and atleast 95% of the particles by number have a diameter less than 7nanometers. Alternatively, at least 95% of the particles by weight havea diameter greater than 1 nanometer and at least 90% of the particles bynumber have a diameter less than 6 nanometers. Dry powder compositionsmay include a solid fine powder diluent such as sugar and areconveniently provided in a unit dose form.

Low boiling propellants generally include liquid propellants having aboiling point of below 65° F. at atmospheric pressure. Generally thepropellant may constitute 50 to 99.9% (w/w) of the composition, and thehalichondrin A, norhalichondrin A, or homohalichondrin A analog mayconstitute 0.1 to 20% (w/w) of the composition. The propellant mayfurther comprise additional ingredients such as a liquid non-ionicand/or solid anionic surfactant and/or a solid diluent (which may have aparticle size of the same order as particles comprising the halichondrinA, norhalichondrin A, or homohalichondrin A analog).

Pharmaceutical compositions of the invention formulated for pulmonarydelivery may provide the halichondrin A, norhalichondrin A, orhomohalichondrin A analog in the form of droplets of a solution and/orsuspension. Such formulations can be prepared, packaged, and/or sold asaqueous and/or dilute alcoholic solutions and/or suspensions, optionallysterile, comprising the halichondrin A, norhalichondrin A, orhomohalichondrin A analog, and may conveniently be administered usingany nebulization and/or atomization device. Such formulations mayfurther comprise one or more additional ingredients including, but notlimited to, a flavoring agent such as saccharin sodium, a volatile oil,a buffering agent, a surface active agent, and/or a preservative such asmethylhydroxybenzoate. The droplets provided by this route ofadministration may have an average diameter in the range from about 0.1to about 200 nanometers.

Formulations described herein as being useful for pulmonary delivery areuseful for intranasal delivery of a pharmaceutical composition of theinvention. Another formulation suitable for intranasal administration isa coarse powder comprising the halichondrin A, norhalichondrin A, orhomohalichondrin A analog and having an average particle from about 0.2to 500 micrometers. Such a formulation is administered by rapidinhalation through the nasal passage from a container of the powder heldclose to the nares.

Formulations for nasal administration may, for example, comprise fromabout as little as 0.1% (w/w) and as much as 100% (w/w) of thehalichondrin A, norhalichondrin A, or homohalichondrin A analog, and maycomprise one or more of the additional ingredients described herein. Apharmaceutical composition can be prepared, packaged, and/or sold in aformulation for buccal administration. Such formulations may, forexample, be in the form of tablets and/or lozenges made usingconventional methods, and may contain, for example, 0.1 to 20% (w/w) ofthe halichondrin A, norhalichondrin A, or homohalichondrin A analog, thebalance comprising an orally dissolvable and/or degradable compositionand, optionally, one or more of the additional ingredients describedherein. Alternately, formulations for buccal administration may comprisea powder and/or an aerosolized and/or atomized solution and/orsuspension comprising the halichondrin A, norhalichondrin A, orhomohalichondrin A analog. Such powdered, aerosolized, and/oraerosolized formulations, when dispersed, may have an average particleand/or droplet size in the range from about 0.1 to about 200 nanometers,and may further comprise one or more of the additional ingredientsdescribed herein.

A pharmaceutical composition can be prepared, packaged, and/or sold in aformulation for ophthalmic administration. Such formulations may, forexample, be in the form of eye drops including, for example, a 0.1/1.0%(w/w) solution and/or suspension of the halichondrin A, norhalichondrinA, or homohalichondrin A analog in an aqueous or oily liquid carrier.Such drops may further comprise buffering agents, salts, and/or one ormore other of the additional ingredients described herein. Otheropthalmically-administrable formulations which are useful include thosewhich comprise the halichondrin A, norhalichondrin A, orhomohalichondrin A analog in microcrystalline form and/or in a liposomalpreparation. Ear drops and/or eye drops are contemplated as being withinthe scope of this invention.

Although the descriptions of pharmaceutical compositions provided hereinare principally directed to pharmaceutical compositions which aresuitable for administration to humans, it will be understood by theskilled artisan that such compositions are generally suitable foradministration to animals of all sorts. Modification of pharmaceuticalcompositions suitable for administration to humans in order to renderthe compositions suitable for administration to various animals is wellunderstood, and the ordinarily skilled veterinary pharmacologist candesign and/or perform such modification with ordinary experimentation.

Halichondrin A, norhalichondrin A, or homohalichondrin A analogsprovided herein are typically formulated in dosage unit form for ease ofadministration and uniformity of dosage. It will be understood, however,that the total daily amount of the halichondrin A, norhalichondrin A, orhomohalichondrin A analog will be decided by the attending physicianwithin the scope of sound medical judgment. The specific therapeuticallyeffective dose level for any particular subject will depend upon avariety of factors including the disease, disorder, or condition beingtreated and the severity of the disorder; the activity of the specifichalichondrin A, norhalichondrin A, or homohalichondrin A analogemployed; the specific composition employed; the age, body weight,general health, sex and diet of the subject; the time of administration,route of administration, and rate of excretion of the specifichalichondrin A, norhalichondrin A, or homohalichondrin A analogemployed; the duration of the treatment; drugs used in combination orcoincidental with the specific halichondrin A, norhalichondrin A, orhomohalichondrin A analog employed; and like factors well known in themedical arts.

The halichondrin A, norhalichondrin A, or homohalichondrin A analogs andcompositions provided herein can be administered by any route, includingenteral (e.g., oral), parenteral, intravenous, intramuscular,intra-arterial, intramedullary, intrathecal, subcutaneous,intraventricular, transdermal, interdermal, rectal, intravaginal,intraperitoneal, topical (as by powders, ointments, creams, and/ordrops), mucosal, nasal, bucal, sublingual; by intratrachealinstillation, bronchial instillation, and/or inhalation; and/or as anoral spray, nasal spray, and/or aerosol. In general the most appropriateroute of administration will depend upon a variety of factors includingthe nature of the agent, the therapeutic regimen, and/or the conditionof the subject. Oral administration is the preferred mode ofadministration. However, in certain embodiments, the subject may not bein a condition to tolerate oral administration, and thus intravenous,intramuscular, and/or rectal administration are also preferredaltermative modes of adminsitration.

The exact amount of a halichondrin A, norhalichondrin A, orhomohalichondrin A analog required to achieve an effective amount willvary from subject to subject, depending, for example, on species, age,and general condition of a subject, severity of the side effects ordisorder, identity of the particular halichondrin A, norhalichondrin A,or homohalichondrin A analog(s), mode of administration, and the like.The desired dosage can be delivered three times a day, two times a day,once a day, every other day, every third day, every week, every twoweeks, every three weeks, or every four weeks. In certain embodiments,the desired dosage can be delivered using multiple administrations(e.g., two, three, four, five, six, seven, eight, nine, ten, eleven,twelve, thirteen, fourteen, or more administrations).

In certain embodiments, an effective amount of a halichondrin A,norhalichondrin A, or homohalichondrin A analog for administration oneor more times a day to a 70 kg adult human may comprise about 0.1 mg toabout 3000 mg, about 0.1 mg to about 2000 mg, about 0.1 mg to about 1000mg, about 0.1 mg to about 100 mg, about 1 mg to about 100 mg, or about10 mg to about 100 mg, of a halichondrin A, norhalichondrin A, orhomohalichondrin A analog per unit dosage form.

In certain embodiments, the halichondrin A, norhalichondrin A, orhomohalichondrin A analogs of the present invention may be administeredat dosage levels sufficient to deliver from about 0.001 mg/kg to about100 mg/kg, from about 0.01 mg/kg to about 100 mg/kg, from about 0.1mg/kg to about 100 mg/kg, from about 0.5 mg/kg to about 100 mg/kg, fromabout 10 mg/kg to about 100 mg/kg, from about 20 mg/kg to about 100mg/kg, and from about 25 mg/kg to about 100 mg/kg, of subject bodyweight per day, one or more times a day, to obtain the desiredtherapeutic effect.

It will be also appreciated that a halichondrin A, norhalichondrin A, orhomohalichondrin A analog or composition, as described herein, can beadministered in combination with one or more additional therapeuticallyactive agents. The halichondrin A, norhalichondrin A, orhomohalichondrin A analog or composition can be administeredconcurrently with, prior to, or subsequent to, one or more additionaltherapeutically active agents. In general, each agent will beadministered at a dose and/or on a time schedule determined for thatagent. In will further be appreciated that the additionaltherapeutically active agent utilized in this combination can beadministered together in a single composition or administered separatelyin different compositions. The particular combination to employ in aregimen will take into account compatibility of the inventivehalichondrin A, norhalichondrin A, or homohalichondrin A analog with theadditional therapeutically active agent and/or the desired therapeuticeffect to be achieved. In general, it is expected that additionaltherapeutically active agents utilized in combination be utilized atlevels that do not exceed the levels at which they are utilizedindividually. In some embodiments, the levels utilized in combinationwill be lower than those utilized individually.

In any of the above described methods, one or more additionaltherapeutic agents (also referred to as the “agent”) may be administeredconcurrently with, prior to, or subsequent to, the halichondrin A,norhalichondrin A, or homohalichondrin A analog of the presentinvention, as described herein. The agent may be added at the same timeas the halichondrin A, norhalichondrin A, or homohalichondrin A analogof the present invention (simultaneous administration), before or afteradministration of the halichondrin A, norhalichondrin A, orhomohalichondrin A analog of the present invention (sequentialadministration), or any combination thereof. For example, in certainembodiments, the agent is administered first, followed by simultaneousadministration of the agent and the halichondrin A, norhalichondrin A,or homohalichondrin A analog of the present invention. In certainembodiments, the halichondrin A, norhalichondrin A, or homohalichondrinA analog of the present invention is administered first, followed bysimultaneous administration of the agent and the halichondrin A,norhalichondrin A, or homohalichondrin A analog of the presentinvention. In any of the above embodiments, either the agent or thehalichondrin A, norhalichondrin A, or homohalichondrin A analog of thepresent invention may be further administered alone after thesimultaneous administration.

Exemplary additional therapeutically active agents include, but are notlimited to, antibiotics, anti-viral agents, anesthetics,anti-coagulants, inhibitors of an enzyme, steroidal agents, steroidal ornon-steroidal anti-inflammatory agents, antihistamine, immunosuppressantagents, antigens, vaccines, antibodies, decongestant, sedatives,opioids, pain-relieving agents, analgesics, anti-pyretics, hormones, andprostaglandins. Therapeutically active agents include small organicmolecules such as drug compounds (e.g., compounds approved by the USFood and Drug Administration as provided in the Code of FederalRegulations (CFR)), peptides, proteins, carbohydrates, monosaccharides,oligosaccharides, polysaccharides, nucleoproteins, mucoproteins,lipoproteins, synthetic polypeptides or proteins, small molecules linkedto proteins, glycoproteins, steroids, nucleic acids, DNAs, RNAs,nucleotides, nucleosides, oligonucleotides, antisense oligonucleotides,lipids, hormones, vitamins, and cells.

In certain embodiments, the additional therapeutically agent is anotheranti-cancer agent. Anti-cancer agents encompass biotherapeuticanti-cancer agents as well as chemotherapeutic agents.

Exemplary biotherapeutic anti-cancer agents include, but are not limitedto, interferons, cytokines (e.g., tumor necrosis factor, interferon α,interferon γ), vaccines, hematopoietic growth factors, monoclonalserotherapy, immunostimulants and/or immunodulatory agents (e.g., IL-1,2, 4, 6, or 12), immune cell growth factors (e.g., GM-CSF) andantibodies (e.g., HERCEPTIN (trastuzumab), T-DM1, AVASTIN (bevacizumab),ERBITUX (cetuximab), VECTIBIX (panitumumab), RITUXAN (rituximab), BEXXAR(tositumomab)).

Exemplary chemotherapeutic agents include, but are not limited to,anti-estrogens (e.g.,tamoxifen, raloxifene, and megestrol), LHRHagonists (e.g., goscrclin and leuprolide), anti-androgens(e.g.,flutamide and bicalutamide), photodynamic therapies (e.g.,vertoporfin (BPD-MA), phthalocyanine, photosensitizer Pc4, anddemethoxy-hypocrellin A (2BA-2-DMHA)), nitrogen mustards (e. g.,cyclophosphamide, ifosfamide, trofosfamide, chlorambucil, estramustine,and melphalan), nitrosoureas (e.g.,carmustine (BCNU) and lomustine(CCNU)), alkylsulphonates (e.g., busulfan and treosulfan), triazenes(e.g.,dacarbazine, temozolomide), platinum containing compounds (e.g.,cisplatin, carboplatin, oxaliplatin), vinca alkaloids (e.g.,vincristine, vinblastine, vindesine, and vinorelbine), taxoids (e.g.,paclitaxel or a paclitaxel equivalent such as nanoparticle albumin-boundpaclitaxel (ABRAXANE), docosahexaenoic acid bound-paclitaxel(DHA-paclitaxel, Taxoprexin), polyglutamate bound-paclitaxel(PG-paclitaxel, paclitaxel poliglumex, CT-2103, XYOTAX), thetumor-activated prodrug (TAP) ANG1005 (Angiopep-2 bound to threemolecules of paclitaxel), paclitaxel-EC-1 (paclitaxel bound to theerbB2-recognizing peptide EC-1), and glucose-conjugated paclitaxel,e.g., 2′-paclitaxel methyl 2-glucopyranosyl succinate; docetaxel,taxol), epipodophyllins (e.g., etoposide, etoposide phosphate,teniposide, topotecan, 9-aminocamptothecin, camptoirinotecan,irinotecan, crisnatol, mytomycin C), anti-metabolites, DHFR inhibitors(e.g., methotrexate, dichloromethotrexate, trimetrexate, edatrexate),IMP dehydrogenase inhibitors (e.g., mycophenolic acid, tiazofurin,ribavirin, and EICAR), ribonuclotide reductase inhibitors (e.g.,hydroxyurea and deferoxamine), uracil analogs (e.g., 5-fluorouracil(5-FU), floxuridine, doxifluridine, ratitrexed, tegafur-uracil,capecitabine), cytosine analogs (e.g.,cytarabine (ara C), cytosinearabinoside, and fludarabine), purine analogs (e.g.,mercaptopurine andThioguanine), Vitamin D3 analogs (e.g.,EB 1089, CB 1093, and KH 1060),isoprenylation inhibitors (e.g.,lovastatin), dopaminergic neurotoxins(e.g.,1-methyl-4-phenylpyridinium ion), cell cycle inhibitors (e.g.,staurosporine), actinomycin (e.g.,actinomycin D, dactinomycin),bleomycin (e.g., bleomycin A2, bleomycin B2, peplomycin), anthracycline(e.g.,daunorubicin, doxorubicin, pegylated liposomal doxorubicin,idarubicin, epirubicin, pirarubicin, zorubicin, mitoxantrone), MDRinhibitors (e.g., verapamil), Ca2+ ATPase inhibitors (e.g.,thapsigargin), imatinib, thalidomide, lenalidomide, tyrosine kinaseinhibitors (e.g., axitinib (AG013736), bosutinib (SKI-606), cediranib(RECENTIN™, AZD2171), dasatinib (SPRYCEL®, BMS-354825), erlotinib(TARCEVA®), gefitinib (IRESSA®), imatinib (Gleevec®, CGP57148B,STI-571), lapatinib (TYKERB®, TYVERB®), lestaurtinib (CEP-701),neratinib (HKI-272), nilotinib (TASIGNA®), semaxanib (semaxinib,SU5416), sunitinib (SUTENT®, SU11248), toceranib (PALLADIA®), vandetanib(ZACTIMA®, ZD6474), vatalanib (PTK787, PTK/ZK), trastuzumab(HERCEPTIN®), bevacizumab (AVASTIN®), rituximab (RITUXAN®), cetuximab(ERBITUX®), panitumumab (VECTIBIX®), ranibizumab (Lucentis®), nilotinib(TASIGNA®), sorafenib (NEXAVAR®), everolimus (AFINITOR®), alemtuzumab(CAMPATH®), gemtuzumab ozogamicin (MYLOTARG®), temsirolimus (TORISEL®),ENMD-2076, PCI-32765, AC220, dovitinib lactate (TKI258, CHIR-258), BIBW2992 (TOVOKTM), SGX523, PF-04217903, PF-02341066, PF-299804, BMS-777607,ABT-869, MP470, BIBF 1120 (VARGATEF®), AP24534, JNJ-26483327, MGCD265,DCC-2036, BMS-690154, CEP-11981, tivozanib (AV-951), OSI-930, MM-121,XL-184, XL-647, and/or XL228), proteasome inhibitors (e.g., bortezomib(VELCADE)), mTOR inhibitors (e.g., rapamycin, temsirolimus (CCI-779),everolimus (RAD-001), ridaforolimus, AP23573 (Ariad), AZD8055(AstraZeneca), BEZ235 (Novartis), BGT226 (Norvartis), XL765 (SanofiAventis), PF-4691502 (Pfizer), GDC0980 (Genetech), SF1126 (Semafoe) andOSI-027 (OSI)), oblimersen, gemcitabine, carminomycin, leucovorin,pemetrexed, cyclophosphamide, dacarbazine, procarbizine, prednisolone,dexamethasone, campathecin, plicamycin, asparaginase, aminopterin,methopterin, porfiromycin, melphalan, leurosidine, leurosine,chlorambucil, trabectedin, procarbazine, discodermolide, carminomycin,aminopterin, and hexamethyl melamine.

Also encompassed by the invention are kits (e.g., pharmaceutical packs).The kits provided may comprise an inventive pharmaceutical compositionor halichondrin A, norhalichondrin A, or homohalichondrin A analog and acontainer (e.g., a vial, ampule, bottle, syringe, and/or dispenserpackage, or other suitable container). In some embodiments, providedkits may optionally further include a second container comprising apharmaceutical excipient for dilution or suspension of an inventivepharmaceutical composition or halichondrin A, norhalichondrin A, orhomohalichondrin A analog. In some embodiments, the inventivepharmaceutical composition or halichondrin A, norhalichondrin A, orhomohalichondrin A analog provided in the container and the secondcontainer are combined to form one unit dosage form.

Methods of Treatment

The present invention also provides methods of using a compound ofFormula (I)-(III) or pharmaceutically acceptable salt thereof, e.g., bytreating or preventing a condition associated with aberrant cellproliferation in a subject in need thereof, or by inhibiting mitosis orinducing cell apoptosis in a subject in need thereof, comprisingadministering to the subject a compound of Formula (I)-(III), or apharmaceutically acceptable salt thereof, or a pharmaceuticalcomposition thereof, in an amount sufficient to treat the condition. Incertain embodiments, a compound of Formula (I)-(III), or apharmaceutically acceptable salt thereof, binds to microtubules andinhibits mitosis or induces cell apoptosis through inhibition ofmicrotubule dynamics in a subject in need thereof. In certainembodiments, a compound of Formula (I)-(III), or a pharmaceuticallyacceptable salt thereof, binds to high affinity sites at the plus end ofexisting microtubules.

In certain embodiments, compounds of Formula (I)-(III) are useful fortreatment of a proliferative disease. Exemplary proliferative diseasesinclude, but are not limited to, tumors, begnin neoplasms, pre-malignantneoplasms (carcinoma in situ), and malignanat neoplasms (cancers).Exemplary cancers include, but are not limited to, acoustic neuroma,adenocarcinoma, adrenal gland cancer, anal cancer, angiosarcoma (e.g.,lymphangiosarcoma, lymphangioendotheliosarcoma, hemangiosarcoma),appendix cancer, benign monoclonal gammopathy, biliary cancer (e.g.,cholangiocarcinoma), bladder cancer, breast cancer (e.g., adenocarcinomaof the breast, papillary carcinoma of the breast, mammary cancer,medullary carcinoma of the breast), brain cancer (e.g., meningioma;glioma, e.g., astrocytoma, oligodendroglioma; medulloblastoma), bronchuscancer, carcinoid tumor, cervical cancer (e.g., cervicaladenocarcinoma), choriocarcinoma, chordoma, craniopharyngioma,colorectal cancer (e.g., colon cancer, rectal cancer, colorectaladenocarcinoma), epithelial carcinoma, ependymoma, endotheliosarcoma(e.g., Kaposi's sarcoma, multiple idiopathic hemorrhagic sarcoma),endometrial cancer (e.g., uterine cancer, uterine sarcoma), esophagealcancer (e.g., adenocarcinoma of the esophagus, Barrett'sadenocarcinoma), Ewing's sarcoma, eye cancer (e.g., intraocularmelanoma, retinoblastoma), familiar hypereosinophilia, gall bladdercancer, gastric cancer (e.g., stomach adenocarcinoma), gastrointestinalstromal tumor (GIST), head and neck cancer (e.g., head and neck squamouscell carcinoma, oral cancer (e.g., oral squamous cell carcinoma (OSCC),throat cancer (e.g., laryngeal cancer, pharyngeal cancer, nasopharyngealcancer, oropharyngeal cancer)), hematological malignancy (e.g., leukemiasuch as acute lymphocytic leukemia (ALL) (e.g., B-cell ALL, T-cell ALL),acute myelocytic leukemia (AML) (e.g., B-cell AML, T-cell AML), chronicmyelocytic leukemia (CML) (e.g., B-cell CML, T-cell CML), and chroniclymphocytic leukemia (CLL) (e.g., B-cell CLL, T-cell CLL); lymphoma suchas Hodgkin lymphoma (HL) (e.g., B-cell HL, T-cell HL) and non-Hodgkinlymphoma (NHL) (e.g., B-cell NHL such as diffuse large cell lymphoma(DLCL) (e.g., diffuse large B-cell lymphoma (DLBCL)), follicularlymphoma, chronic lymphocytic leukemia/small lymphocytic lymphoma(CLL/SLL), mantle cell lymphoma (MCL), marginal zone B-cell lymphomas(e.g., mucosa-associated lymphoid tissue (MALT) lymphomas, nodalmarginal zone B-cell lymphoma, splenic marginal zone B-cell lymphoma),primary mediastinal B-cell lymphoma, Burkitt lymphoma, lymphoplasmacyticlymphoma (i.e., “Waldenström's macroglobulinemia”), hairy cell leukemia(HCL), immunoblastic large cell lymphoma, precursor B-lymphoblasticlymphoma and primary central nervous system (CNS) lymphoma; and T-cellNHL such as precursor T-lymphoblastic lymphoma/leukemia, peripheralT-cell lymphoma (PTCL) (e.g., cutaneous T-cell lymphoma (CTCL) (e.g.,mycosis fungoides, Sezary syndrome), angioimmunoblastic T-cell lymphoma,extranodal natural killer T-cell lymphoma, enteropathy type T-celllymphoma, subcutaneous panniculitis-like T-cell lymphoma, anaplasticlarge cell lymphoma); a mixture of one or more leukemia/lymphoma asdescribed herein; and multiple myeloma (MM)), heavy chain disease (e.g.,alpha chain disease, gamma chain disease, mu chain disease),hemangioblastoma, inflammatory myofibroblastic tumors, immunocyticamyloidosis, kidney cancer (e.g., nephroblastoma a.k.a. Wilms' tumor,renal cell carcinoma), liver cancer (e.g., hepatocellular cancer (HCC),malignant hepatoma), lung cancer (e.g., bronchogenic carcinoma, smallcell lung cancer (SCLC), non-small cell lung cancer (NSCLC),adenocarcinoma of the lung), leiomyosarcoma (LMS), mastocytosis (e.g.,systemic mastocytosis), myelodysplastic syndrome (MDS), mesothelioma,myeloproliferative disorder (MPD) (e.g., polycythemia Vera (PV),essential thrombocytosis (ET), agnogenic myeloid metaplasia (AMM) a.k.a.myelofibrosis (MF), chronic idiopathic myelofibrosis, chronic myelocyticleukemia (CML), chronic neutrophilic leukemia (CNL), hypereosinophilicsyndrome (HES)), neuroblastoma, neurofibroma (e.g., neurofibromatosis(NF) type 1 or type 2, schwannomatosis), neuroendocrine cancer (e.g.,gastroenteropancreatic neuroendocrine tumor (GEP-NET), carcinoid tumor),osteosarcoma, ovarian cancer (e.g., cystadenocarcinoma, ovarianembryonal carcinoma, ovarian adenocarcinoma), papillary adenocarcinoma,pancreatic cancer (e.g., pancreatic andenocarcinoma, intraductalpapillary mucinous neoplasm (IPMN), Islet cell tumors), penile cancer(e.g., Paget's disease of the penis and scrotum), pinealoma, primitiveneuroectodermal tumor (PNT), prostate cancer (e.g., prostateadenocarcinoma), rectal cancer, rhabdomyosarcoma, salivary gland cancer,skin cancer (e.g., squamous cell carcinoma (SCC), keratoacanthoma (KA),melanoma, basal cell carcinoma (BCC)), small bowel cancer (e.g.,appendix cancer), soft tissue sarcoma (e.g., malignant fibroushistiocytoma (MFH), liposarcoma, malignant peripheral nerve sheath tumor(MPNST), chondrosarcoma, fibrosarcoma, myxosarcoma), sebaceous glandcarcinoma, sweat gland carcinoma, synovioma, testicular cancer (e.g.,seminoma, testicular embryonal carcinoma), thyroid cancer (e.g.,papillary carcinoma of the thyroid, papillary thyroid carcinoma (PTC),medullary thyroid cancer), urethral cancer, vaginal cancer and vulvarcancer (e.g., Paget's disease of the vulva). In certain embodiments, thecancer is a hematological malignancy. In certain embodiments, the canceris lymphoma. In certain embodiments, the cancer is leukemia.

A “subject” to which administration is contemplated includes, but is notlimited to, humans (i.e., a male or female of any age group, e.g., apediatric subject (e.g, infant, child, adolescent) or adult subject(e.g., young adult, middle-aged adult or senior adult)) and/or othernon-human animals, for example mammals (e.g., primates (e.g., cynomolgusmonkeys, rhesus monkeys); commercially relevant mammals such as cattle,pigs, horses, sheep, goats, cats, and/or dogs), birds (e.g.,commercially relevant birds such as chickens, ducks, geese, and/orturkeys), reptiles, amphibians, and fish. In certain embodiments, thenon-human animal is a mammal. The non-human animal may be a male orfemale and at any stage of development. A non-human animal may be atransgenic animal.

As used herein, and unless otherwise specified, the terms “treat,”“treating,” and “treatment” contemplate an action that occurs while asubject is suffering from the specified disease, disorder or condition,which reduces the severity of the disease, disorder or condition, orretards or slows the progression of the disease, disorder or condition(“therapeutic treatment”), and also contemplates an action that occursbefore a subject begins to suffer from the specified disease, disorderor condition (“prophylactic treatment”).

In general, the “effective amount” of a compound refers to an amountsufficient to elicit the desired biological response. As will beappreciated by those of ordinary skill in this art, the effective amountof a compound of the invention may vary depending on such factors as thedesired biological endpoint, the pharmacokinetics of the compound, thedisease being treated, the mode of administration, and the age, health,and condition of the subject. An effective amount encompassestherapeutic and prophylactic treatment.

As used herein, and unless otherwise specified, a “therapeuticallyeffective amount” of a compound is an amount sufficient to provide atherapeutic benefit in the treatment of a disease, disorder orcondition, or to delay or minimize one or more symptoms associated withthe disease, disorder, or condition. A therapeutically effective amountof a compound means an amount of therapeutic agent, alone or incombination with other therapies, which provides a therapeutic benefitin the treatment of the disease, disorder or condition. The term“therapeutically effective amount” can encompass an amount that improvesoverall therapy, reduces or avoids symptoms or causes of disease orcondition, or enhances the therapeutic efficacy of another therapeuticagent.

As used herein, and unless otherwise specified, a “prophylacticallyeffective amount” of a compound is an amount sufficient to prevent adisease, disorder or condition, or one or more symptoms associated withthe disease, disorder or condition, or prevent its recurrence. Aprophylactically effective amount of a compound means an amount of atherapeutic agent, alone or in combination with other agents, whichprovides a prophylactic benefit in the prevention of the disease,disorder or condition. The term “prophylactically effective amount” canencompass an amount that improves overall prophylaxis or enhances theprophylactic efficacy of another prophylactic agent.

As used herein “inhibition”, “inhibiting”, “inhibit” and “inhibitor”,and the like, refer to the ability of a compound to reduce, slow, haltor prevent activity of a particular biological process (e.g.,microtubule dynamics or growth) in a cell relative to vehicle.

Methods of Synthesis and Intermediates

The synthesis of halichondrin A was planned from 4c and 5. The righthalf 4c was disconnected retrosynthetically into the C1-C19 and C20-C38building blocks 6 and 7 (see Scheme 1). Such a synthetic scheme enablesthe proposed synthesis of 4c from 6 and 7 to be achieved by recentlydeveloped asymmetric Ni/Cr-mediated coupling, followed by base-inducedcyclization.^(1,2) The specified route also leads to certain additionaladvantages. For example, two known building blocks 5 and 7 can also beutilized.³ The current synthetic scheme for halichondrin A alsopossesses a higher degree of convergency than in the previous routes.⁴Furthermore, the specified synthetic approach can be extended to thesynthesis of halichondrins B and C (see building blocks 6-B and 6-C).

The central question for the synthesis of building block 6 was how toconstruct the C8-C14 polycycle of halichondrin A. Through the modelstudies conducted in connection with the synthesis of halichondrin C,valuable information was gained to address this question.⁵ Scheme 2summarizes a transformation of 8 into β-10 possessing the C8-C14polycycle of halichondrin A. This transformation involves: (1) selectiveTBS-deprotection of both C9-OTBS (equatorial) and C11-OTBS (acyclic)over C8-OTBS (axial), (2) oxy-Michael addition of the resultantC9-alcohol to ynone 8, to form preferentially E-isomer with assistanceof hydrogen-bonding stabilization, (3) stereoselective DMDO-epoxidationfrom convex face, and (4) acid-promoted ketalization to form 3-10.Interestingly, DMDO-epoxidation of the corresponding Z-isomer Z-9,followed by acid-treatment, gave α-10 non-contaminated from β-10,thereby demonstrating the high stereoselectivity of DMDO oxidation. Ontreatment with p-anisaldehyde dimethyl acetal in the presence ofcamphorsulfonic acid (CSA), β-10 gave single p-methoxybenzylidene acetal11.⁶

Guided by the model study, the C1-C19 building block 6a was prepared(Scheme 3). The coupling of aldehyde 13a with iodoacetylene 12 waseffectively achieved with catalytic asymmetric Ni/Cr-mediated coupling.lodoacetylenes are far more reactive than iodoolefins in the Cr-mediatedcoupling.⁷ This suggested the possibility that the (12+13a) coupling canbe achieved without interference from the C19-iodoolefin present in 6a.Indeed, it was found that the coupling was effectively achieved with atrace amount of Ni-catalyst or without added Ni-catalyst. At present,however, it is not clear whether a trace amount of Ni-catalyst isrequired for this coupling.⁷ As the resultant allylic alcohol isoxidized to the ketone, the C14 stereochemistry outcome is not an issuefor this coupling. However, the Cr-catalyst derived from a sulfonamideligand such as sulfonamide-I (Scheme 4) significantly accelerates thecoupling. Interestingly, (R)-ligand was found to be more effective than(S)-ligand. The coupling was conducted routinely with 15-20 mol %Cr-catalyst, however, the catalyst loading was improved up to 5 mol %with the iodoacetylene with TES, i.e., R=TES in 12, without a loss ofthe coupling efficiency.

In ligands of Scheme 4, R^(L1) is substituted or unsubstituted C₁₋₆alkyl. In certain embodiments, R^(L1) is isopropyl. In certainembodiments, R^(L1) is t-butyl. In certain embodiments, the carbon towhich R^(L1) is attached is in the (R)-configuration. In certainembodiments, the carbon to which R^(L1) is attached is in the(S)-configuration. In ligands of Scheme 4, R^(L2) is substituted orunsubstituted C₁₋₆ alkyl or substituted or unsubstituted aryl. Incertain embodiments, R^(L2) is methyl. In certain embodiments, R^(L2) issubstituted or unsubstituted phenyl. In certain embodiments, R^(L2) isphenyl substituted with at least one halogen. In certain embodiments,R^(L2) is phenyl substituted with at least two halogens. In ligands ofScheme 4, each R^(L3) is independently substituted or unsubstitutedalkoxy or substituted or unsubstituted carbocyclyl and p is 1, 2, 3, or4. In certain embodiments, at least one R^(L3) is methoxy; and p is 1 or2. In certain embodiments, at least one R^(L3) is substituted orunsubstituted 5-6 membered carbocyclyl. In certain embodiments, at leastone R^(L3) is substituted or unsubstituted cyclohexyl. In certainembodiments, at least one R^(L3) is cyclohexyl substituted with at leastone methyl. In certain embodiments, at least one R^(L3) is cyclohexylsubstituted with at least two methyls. In ligands of Scheme 4, eachR^(L4) is independently substituted or unsubstituted C₁₋₆ alkyl orsubstituted or unsubstituted aryl. In ligands of Scheme 4, each R^(L5)is independently hydrogen or substituted or unsubstituted alkoxy. Incertain embodiments, both of R^(L5) are hydrogen. In certainembodiments, at least one R^(L5) is methoxy. In certain embodiments,both of R^(L5) are methoxy.

After oxidation of the propargyl alcohol, 14a was subjected to selectiveTBS-deprotection conditions to give enone 15 (E-isomer: 62%; Z-isomer:6%). DMDO-oxidation, followed by acid-treatment and then p-anisaldehydedimethyl acetal, furnished the desired C1-C19 building block 6a in 45%overall yield. However, the product thus obtained was a 2:1 mixture ofdesired 6a and acetylene 16. An NMR analysis showed that this by-productformation took place during the DMDO-step.

A literature search revealed no example known for DMDO-mediatedtransformation of iodoolefins to acetylenes.⁸ Nevertheless, formation of16 is likely caused by the DMDO-oxidation of the iodine to iodosointermediate A, followed by syn-elimination reported by Reich.⁹Alternatively, the synthesis was carried out using bromoolefin aldehyde13b. The synthesis of this series proceeded in the parallel way with the13a series, except for: (1) as anticipated, there was no acetyleneby-product 16 formed and (2) the efficiency of Ni/Cr-mediated(12+13b)-coupling was slightly higher in this series (70% overall yieldfrom 15).

Coupling of the C1-C19 building block 6b with the C20-C38 building block7 was realized by Ni/Cr-mediated reaction in the presence of theCr-catalyst derived from (R)-sulfonamide II (Scheme 5).² However, toovercome the poorer reactivity of the bromoolefin of 6b, this couplingwas carried out with 40 mol % Cr-reagent. The induced cyclization of theresultant allylic alcohol with AgOTf-Ag₂O gave desired product 17 in 70%overall yield from 7, with 20:1 stereoselectivity.¹⁰ On treatment withaq. LiOH, both acetate and methyl ester of 17 were hydrolyzed to yieldthe expected seco-acid, macrolactonization of which was effected withShiina's reagent to furnish 18 in 77% overall yield.¹¹ Selectivedeprotection of the 1°-TBS at C38 over the 2°-TBS at C35 was effectedwith HF•py and imidazole in MeCN at 4° C., to furnish the halichondrin-Aright-half 19 in 85% yield. After Dess-Martin oxidation, 19 wassubjected to Ni/Cr-mediated coupling with the halichondrin left-half 5,followed by oxidation, to furnish the trans-enone 20 in 85% yield(Scheme 6). Once again, (S)-sulfonamide-I was used to accelerate thecoupling rate.

The following chemical transformations were required to convert 20 tohalichondrin A: (1) deprotection of the five TBS groups, (2) hemiketalformation at C44, (3) oxy-Michael addition of the resultant hemiketalhydroxyl group to the α,β-unsaturated ketone to form the[6,6]-spiroketal at C44, (4) deprotection of the C41-MPM group, (5)formation of [5,5]-spiroketal at C38, and (6) deprotection of theanisylidene group at C12/C13. The anisylidene group could be removed byPPTS in protic solvent and therefore the transformation of 20 intohalichondrin A could be achieved with use of a 3-step protocol. Compound20 was subjected to TBAF, DDQ, and then PPTS treatments. In the thirdstep (PPTS in isopropanol at RT), the anisylidene group was indeedremoved, but two major products (ca. 3:2 ratio) were formed. Massspectral (MS) and ¹H NMR analysis suggested that the major and minorproducts were likely to correspond to C38-epi-halichondrin A andhalichondrin A, respectively.

For this reason, the acid-catalyzed equilibration of the[5,5]-spiroketal at C38 was studied (see FIG. 2). Compared with[6,6]-spiroketals, the stereochemical behaviors of [5,5]-spiroketals arecomplex,¹² and it is not straightforward to suggest a chemical means tofavor halichondrin A over C38-epi-halichondrin A or vice versa. Afternumerous attempts, a simple, but remarkably effective method wasdiscovered to favor either halichondrin A (21) or C38-epi-halichondrin A(22) in the equilibrium; 21 and 22 were formed as the major stereoisomeron treatment with TMSOTf in CH₂Cl₂ or Et₂O, respectively.¹³ It isworthwhile noting: (1) no furan formation was observed under theconditions employed and (2) both halichondrins B and C exhibited theidentical reactivity.

Without wishing to be limited to any particular theory, but realizingthat solvents play a key role,¹⁴ a speculative mechanistic explanationis proposed; the C35-C44 moiety of halichondrins provides apolyether-type cavity for cations such as Me₃Si⁺ innon-oxygen-containing solvents, which shifts the equilibration in favorto halichondrin A (Scheme 5). In oxygen-containing solvents, the cavityeffect is cancelled out with solvents and an unfavorable dipole-dipoleinteraction between the C38-O and C40-O bonds in halichondrin A shiftsthe equilibrium towards C38-epi-halichondrin A.

Based on the insight on the [5,5]-spiroketal behavior, a total synthesisof halichondrin A was completed in a stereoselective manner. Namely, theproduct mixture obtained in the PPTS step was subjected to theTMSOTf-promoted equilibration, followed by chromatographic separation,to furnish synthetic halichondrin A (21) in 39% overall yield from 20,along with C38-epi-halichondrin A (22; ca. 3%).

Norhalichondrin A (24) was synthesized with coupling 19 and 23 (Scheme7).¹⁵ It should be noted that 23 was the left half used for thesynthesis of norhalichondrin B.¹⁶ Synthetic norhalichondrin A (24) thusobtained was confirmed to be identical with natural norhalichondrin A(¹H- and ¹³C-NMR, HR-MS, TLC), thereby establishing the structure of thehalichondrin right-half 19. Noteworthily, norhalichondrin A (24) playedthe central role in structure elucidation of this class of naturalproducts, i.e., the X-ray structure analysis of its p-bromophenacylester. Taken together, the stereochemistry of the two building blocks 5and 19 used for the current halichondrin A synthesis were unambiguouslyestablished.

Three chiral centers at C38, C40, and C44 were introduced at thetransformation from the enone 20 to the final product. The fact thatnorhalichondrin A (24) was successfully obtained by using the virtuallysame procedure strongly suggests that the newly introduced three chiralcenters match with those present in the halichondrin class naturalproducts. Detailed NMR analysis provided further evidence. The panel inFIG. 4 summarizes the proton chemical shift differences betweennorhalichondrin A and synthetic halichondrin A (dark gray) and synthetichalichondrin A and homohalichondrin A (light gray). This comparisondemonstrates that these three halichondrins share the same right-halfstructure. Similarly, the panel in FIG. 5 shows the proton chemicalshift differences between synthetic halichondrin A and halichondrin B(dark gray) and halichondrin C and synthetic halichondrin A (lightgray), thereby demonstrating that these three halichondrins share thesame left-half structure. The two NMR comparisons once again proved thathalichondrin A obtained through the total synthesis is a uniquecompound.

Provided herein are synthetic intermediates for the synthesis ofhalichondrin A, homohalichondrin A, and norhalichondrin A and analogsthereof. In one aspect, provided are compounds of Formula (A-1):

and pharmaceutically acceptable salts thereof, wherein:

R^(P17), R^(P18), and R^(P19) are each independently hydrogen,substituted or unsubstituted alkyl, or an oxygen protecting group;

R^(Z1) is —CO₂R^(Z1a), wherein R^(Z1a) is hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group; and

X^(A) is hydrogen or a halogen.

In another aspect, provided are compounds of Formula (B-1):

and pharmaceutically acceptable salts thereof, wherein:

R^(P17) and R^(P18) are each independently hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group;

R^(Z1) is —CO₂R^(Z1a), wherein R^(Z1a) is hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group;

R^(Z2) is a halogen or a leaving group; and

R^(Z3) is a halogen.

In another aspect, provided are compounds of Formula (C-1):

and pharmaceutically acceptable salts thereof, wherein:

R^(Z1) is —CO₂R^(Z1a), wherein R^(Z1a) is hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group;

R^(Z2) is a halogen or a leaving group;

R^(Z3) is a halogen;

R^(X) is —OR^(X1), wherein R^(X1) is hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group;

R^(Y) is —OR^(Y1), wherein R^(Y1) is hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group; and

R^(X) and R^(Y) can be taken with their intervening atoms to form asubstituted or unsubstituted heterocyclic ring.

In another aspect, provided are compounds of Formula (D-1):

and pharmaceutically acceptable salts thereof, wherein:

R^(Z1) is —CO₂R^(Z1a), wherein R^(Z1a) is hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group;

R^(Z4) is —CH₂OR^(Z4a) or —CHO, wherein R^(Z4a) is hydrogen, substitutedor unsubstituted alkyl, or an oxygen protecting group;

R^(P4) and R^(P5) are each independently hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group;

R³ and R⁵ are each independently hydrogen, halogen, or substituted orunsubstituted alkyl;

each instance of R⁴ is independently hydrogen, halogen, substituted orunsubstituted alkyl, or two R⁴ groups can be taken together to form a

group;

each instance of R⁶ is independently hydrogen, halogen, substituted orunsubstituted alkyl, or two R⁶ groups can be taken together to form a

group;

R^(X) is —OR^(X1), wherein R^(X1) is hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group;

R^(Y) is —OR^(Y1), wherein R^(Y1) is hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group; and

R^(X) and R^(Y) can be taken with their intervening atoms to form asubstituted or unsubstituted heterocyclic ring.

In another aspect, provided are compounds of Formula (E-1):

and pharmaceutically acceptable salts thereof, wherein:

R^(Z4) is —CH₂OR^(Z4a) or —CHO, wherein R^(Z4a) is hydrogen, substitutedor unsubstituted alkyl, or an oxygen protecting group;

R^(P4) is hydrogen, substituted or unsubstituted alkyl, or an oxygenprotecting group;

R³ and R⁵ are each independently hydrogen, halogen, or substituted orunsubstituted alkyl;

each instance of R⁴ is independently hydrogen, halogen, substituted orunsubstituted alkyl, or two R⁴ groups can be taken together to form a

group;

each instance of R⁶ is independently hydrogen, halogen, substituted orunsubstituted alkyl, or two R⁶ groups can be taken together to form a

group;

R^(X) is —OR^(X1), wherein R^(X1) is hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group;

R^(Y) is —OR^(Y1), wherein R^(Y1) is hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group; and

R^(X) and R^(Y) can be taken with their intervening atoms to form asubstituted or unsubstituted heterocyclic ring.

In another aspect, provided are compounds of Formula (F-1):

and pharmaceutically acceptable salts thereof, wherein:

R^(P1), R^(P2), R^(P3), R^(P4), R^(P6), and R^(P7) are eachindependently hydrogen, substituted or unsubstituted alkyl, or an oxygenprotecting group;

R¹, R², R³, and R⁵ are each independently hydrogen, halogen, orsubstituted or unsubstituted alkyl;

each instance of R⁴ is independently hydrogen, halogen, substituted orunsubstituted alkyl, or two R⁴ groups can be taken together to form a

group;

each instance of R⁶ is independently hydrogen, halogen, substituted orunsubstituted alkyl, or two R⁶ groups can be taken together to form a

group;

R^(X) is —OR^(X1), wherein R^(X1) is hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group;

R^(Y) is —OR^(Y1), wherein R^(Y1) is hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group; and

R^(X) and R^(Y) can be taken with their intervening atoms to form asubstituted or unsubstituted heterocyclic ring.

In another aspect, provided are compounds of Formula (G-1):

and pharmaceutically acceptable salts thereof, wherein:

R^(P8), R^(P9), R^(P10), and R^(P11) are each independently hydrogen,substituted or unsubstituted alkyl, or an oxygen protecting group;

R¹, R², R³, and R⁵ are each independently hydrogen, halogen, orsubstituted or unsubstituted alkyl;

each instance of R⁴ is independently hydrogen, halogen, substituted orunsubstituted alkyl, or two R⁴ groups can be taken together to form a

group;

each instance of R⁶ is independently is hydrogen, halogen, substitutedor unsubstituted alkyl, or two R⁶ groups can be taken together to form a

group;

R⁷ is hydrogen, substituted or unsubstituted alkyl, or an oxygenprotecting group;

R^(X) is —OR^(X1), wherein R^(X1) is hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group;

R^(Y) is —OR^(Y1), wherein R^(Y1) is hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group; and

R^(X) and R^(Y) can be taken with their intervening atoms to form asubstituted or unsubstituted heterocyclic ring.

In another aspect, provided are compounds of Formula (H-1):

and pharmaceutically acceptable salts thereof, wherein:

R^(P12), R^(P13), R^(P14), R^(P15) and R^(P16) are each independentlyhydrogen, substituted or unsubstituted alkyl, or an oxygen protectinggroup;

R¹, R², R³, and R⁵ are each independently hydrogen, halogen, orsubstituted or unsubstituted alkyl;

each instance of R⁴ is independently hydrogen, halogen, substituted orunsubstituted alkyl, or two R⁴ groups can be taken together to form a

group;

each instance of R⁶ is independently hydrogen, halogen, substituted orunsubstituted alkyl, or two R⁶ groups can be taken together to form a

group;

R^(X) is —OR^(X1), wherein R^(X1) is hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group;

R^(Y) is —OR^(Y1), wherein R^(Y1) is hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group; and

R^(X) and R^(Y) can be taken with their intervening atoms to form asubstituted or unsubstituted heterocyclic ring.

In another aspect, provided are compounds of Formula (I-1):

and pharmaceutically acceptable salts thereof, wherein:

R^(P1), R^(P2), R^(P3), R^(P6), and R^(P7) are each independentlyhydrogen, substituted or unsubstituted alkyl, or an oxygen protectinggroup;

R¹ and R² are each independently hydrogen, halogen, or substituted orunsubstituted alkyl; and

X is a halogen.

In another aspect, provided are compounds of Formula (J-1):

and pharmaceutically acceptable salts thereof, wherein:

R^(Z5) is —CH₂OR^(Z5a) or —CHO, wherein R^(Z5a) is hydrogen, substitutedor unsubstituted alkyl, or an oxygen protecting group;

R^(Z4) is —CH₂OR^(Z4a) or —CHO, wherein R^(Z4a) is hydrogen, substitutedor unsubstituted alkyl, or an oxygen protecting group;

R^(P4) and R^(P5) are each independently hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group;

R³ and R⁵ are each independently hydrogen, halogen, or substituted orunsubstituted alkyl; and

each instance of R⁴ is independently is hydrogen, halogen, substitutedor unsubstituted alkyl, or two R⁴ groups can be taken together to form a

group.

In another aspect, provided are compounds of Formula (K-1):

and pharmaceutically acceptable salts thereof, wherein:

R^(P8), R^(P9), and R^(P10) are each independently hydrogen, substitutedor unsubstituted alkyl, or an oxygen protecting group;

R¹ and R² are each independently hydrogen, halogen, or substituted orunsubstituted alkyl;

R⁷ is hydrogen, substituted or unsubstituted alkyl, or an oxygenprotecting group; and

X is a halogen.

In another aspect, provided are compounds of Formula (L-1):

and pharmaceutically acceptable salts thereof, wherein:

R^(P12), R^(P13), R^(P14), and R^(P16) are each independently hydrogen,substituted or unsubstituted alkyl, or an oxygen protecting group;

R¹ and R² are each independently hydrogen, halogen, or substituted orunsubstituted alkyl; and

X is a halogen.

In another aspect, provided are any one of the following compounds:

Groups X and X^(A)

As generally described herein, X is halogen (e.g., —F, —Cl, —Br, or —I).In certain embodiments, X is bromine. In certain embodiments, X isiodine.

As generally described herein, X^(A) is hydrogen or halogen (e.g., —F,—Cl, —Br, or —I). In certain embodiments, X^(A) is bromine. In certainembodiments, X^(A) is iodine.

Groups R^(Z1), R^(Z4), R^(Z5), R^(Z1a), R^(Z4a), and R^(Z5a)

As generally described herein, R^(Z1) is —CO₂R^(Z1a), wherein R^(Z1a) ishydrogen, substituted or unsubstituted alkyl, or an oxygen protectinggroup.In certain embodiments, R^(Z1a) is hydrogen. In certainembodiments, R^(Z1a) is substituted or unsubstitituted alkyl. In certainembodiments, R^(Z1a) is substituted or unsubstituted C₁₋₆ alkyl. Incertain embodiments, R^(Z1a) is substituted or unsubstituted, branchedC₁₋₆ alkyl. In certain embodiments, R^(Z1a) is unsubstituted C₁₋₆ alkyl.In certain embodiments, R^(Z1a) is methyl. In certain embodiments,R^(Z1a) is ethyl. In certain embodiments, R^(Z1a) is propyl. In certainembodiments, R^(Z1a) is iso-propyl. In certain embodiments, R^(Z1a) ist-butyl. In certain embodiments, R^(Z1a) is an oxygen protecting group.In certain embodiments, R^(Z1a) is a silyl protecting group. In certainembodiments, R^(Z1a) is a trialkyl silyl protecting group. In certainembodiments, R^(Z1a) is a t-butyldimethylsilyl protecting group. Incertain embodiments, R^(Z1a) is a trimethylsilyl protecting group. Incertain embodiments, R^(Z1a) is a triethylsilyl protecting group. Incertain embodiments, R^(Z1a) is a t-butyldiphenylsilyl protecting group.In certain embodiments, R^(Z1a) is a triisopropylsilyl protecting group.In certain embodiments, R^(Z1a) is a benzylic protecting group. Incertain embodiments, R^(Z1a) is a p-methoxybenzyl protecting group. Incertain embodiments, R^(Z1a) is an acyl protecting group. In certainembodiments, R^(Z1a) is an acetyl protecting group. In certainembodiments, R^(Z1a) is a benzoyl protecting group. In certainembodiments, R^(Z1a) is a p-nitro benzoyl protecting group. In certainembodiments, R^(Z1a) is a pivaloyl protecting group. In certainembodiments, R^(Z1a) is a t-butyl carbonate (BOC) protecting group. Incertain embodiments, R^(Z1a) is an acetal protecting group. In certainembodiments, R^(Z1a) is a tetrahydropyranyl protecting group. In certainembodiments, R^(Z1a) is an alkoxyalkyl protecting group. In certainembodiments, R^(Z1a) is an ethoxyethyl protecting group.

As generally described herein, R^(Z4) is —CH₂OR^(Z4a) or —CHO, whereinR^(Z4a) is hydrogen, substituted or unsubstituted alkyl, or an oxygenprotecting group. In certain embodiments, R^(Z4a) is hydrogen. Incertain embodiments, R^(Z4a) is substituted or unsubstitituted alkyl. Incertain embodiments, R^(Z4a) is substituted or unsubstituted C₁₋₆ alkyl.In certain embodiments, R^(Z4a) is substituted or unsubstituted,branched C₁₋₆ alkyl. In certain embodiments, R^(Z4a) is unsubstitutedC₁₋₆ alkyl. In certain embodiments, R^(Z4a) is methyl. In certainembodiments, R^(Z4a) is ethyl. In certain embodiments, R^(Z4a) ispropyl. In certain embodiments, R^(Z4a) is iso-propyl. In certainembodiments, R^(Z4a) is t-butyl. In certain embodiments, R^(Z4a) is anoxygen protecting group. In certain embodiments, R^(Z4a) is a silylprotecting group. In certain embodiments, R^(Z4a) is a trialkyl silylprotecting group. In certain embodiments, R^(Z4a) is at-butyldimethylsilyl protecting group. In certain embodiments, R^(Z4a)is a trimethylsilyl protecting group. In certain embodiments, R^(Z4a) isa triethylsilyl protecting group. In certain embodiments, R^(Z4a) is at-butyldiphenylsilyl protecting group. In certain embodiments, R^(Z4a)is a triisopropylsilyl protecting group. In certain embodiments, R^(Z4a)is a benzylic protecting group. In certain embodiments, R^(Z4a) is ap-methoxybenzyl protecting group. In certain embodiments, R^(Z4a) is anacyl protecting group. In certain embodiments, R^(Z4a) is an acetylprotecting group. In certain embodiments, R^(Z4a) is a benzoylprotecting group. In certain embodiments, R^(Z4a) is a p-nitro benzoylprotecting group. In certain embodiments, R^(Z4a) is a pivaloylprotecting group. In certain embodiments, R^(Z4a) is a t-butyl carbonate(BOC) protecting group. In certain embodiments, R^(Z4a) is an acetalprotecting group. In certain embodiments, R^(Z4a) is a tetrahydropyranylprotecting group. In certain embodiments, R^(Z4a) is an alkoxyalkylprotecting group. In certain embodiments, R^(Z4a) is an ethoxyethylprotecting group.

As generally described herein, R^(Z5) is —CH₂OR^(Z5a) or —CHO, whereinR^(Z5a) is hydrogen, substituted or unsubstituted alkyl, or an oxygenprotecting group. In certain embodiments, R^(Z5a) is hydrogen. Incertain embodiments, R^(Z5a) is substituted or unsubstitituted alkyl. Incertain embodiments, R^(Z5a) is substituted or unsubstituted C₁₋₆ alkyl.In certain embodiments, R^(Z5a) is substituted or unsubstituted,branched C₁₋₆ alkyl. In certain embodiments, R^(Z5a) is unsubstitutedC₁₋₆ alkyl. In certain embodiments, R^(Z5a) is methyl. In certainembodiments, R^(Z5a) is ethyl. In certain embodiments, R^(Z5a) ispropyl. In certain embodiments, R^(Z5a) is iso-propyl. In certainembodiments, R^(Z5a) is t-butyl. In certain embodiments, R^(Z5a) is anoxygen protecting group. In certain embodiments, R^(Z5a) is a silylprotecting group. In certain embodiments, R^(Z5a) is a trialkyl silylprotecting group. In certain embodiments, R^(Z5a) is at-butyldimethylsilyl protecting group. In certain embodiments, R^(Z5a)is a trimethylsilyl protecting group. In certain embodiments, R^(Z5a) isa triethylsilyl protecting group. In certain embodiments, R^(Z5a) is at-butyldiphenylsilyl protecting group. In certain embodiments, R^(Z5a)is a triisopropylsilyl protecting group. In certain embodiments, R^(Z5a)is a benzylic protecting group. In certain embodiments, R^(Z5a) is ap-methoxybenzyl protecting group. In certain embodiments, R^(Z5a) is anacyl protecting group. In certain embodiments, R^(Z5a) is an acetylprotecting group. In certain embodiments, R^(Z5a) is a benzoylprotecting group. In certain embodiments, R^(Z5a) is a p-nitro benzoylprotecting group. In certain embodiments, R^(Z5a) is a pivaloylprotecting group. In certain embodiments, R^(Z5a) is a t-butyl carbonate(BOC) protecting group. In certain embodiments, R^(Z5a) is an acetalprotecting group. In certain embodiments, R^(Z5a) is a tetrahydropyranylprotecting group. In certain embodiments, R^(Z5a) is an alkoxyalkylprotecting group. In certain embodiments, R^(Z5a) is an ethoxyethylprotecting group.

Groups R^(Z2) and R^(Z3)

As generally described herein, R^(Z2) is halogen (e.g., —F, —Cl, —Br, or—I) or a leaving group. In certain embodiments, R^(Z2) is chlorine. Incertain embodiments, R^(z2) is bromine. In certain embodiments, R^(Z2)is iodine.

As generally described herein, R^(Z3) is halogen (e.g., —F, —Cl, —Br, or—I). In certain embodiments, R^(Z3) is bromine. In certain embodiments,R^(Z3) is iodine.

General Description of Synthesis

Preparation of halichondrin A, norhalichondrin A, and homohalichondrin Aand analogs of the present invention is further described herein.However, the below description of synthesizing these compounds is one ofmany methods of their preparation and should not limit the invention asa whole.

In certain embodiments, preparation of compounds of Formula (I) orpharmaceutically acceptable salts thereof comprises cyclizing anintermediate compound of Formula (F-1) or salt thereof (see Scheme S1).In certain embodiments, when a compound of Formula (F-1) is protected(e.g., with silyl or benzylic protecting groups), the synthetic routecomprises a deprotection step prior to cyclization. In certainembodiments, deprotection of a compound of Formula (F-1) comprises asource of fluoride (e.g., TBAF, HF•pyridine). In certain embodiments,deprotection of a compound of Formula (F-1) comprises a hydrogenolysis(e.g., a palladium or nickel catalyst and H₂) or oxidation (e.g., DDQ)step. In certain embodiments, the cyclization conditions comprise anacid. In certain embodiments, the cyclization conditions comprise aBronsted acid (i.e., a source of H⁺). In certain embodiments, thecyclization conditions comprise an organic acid (e.g., PPTS). In certainembodiments, the cyclization conditions provide a compound of Formula(I) as a single diastereomer. In certain embodiments, the cyclizationconditions provide a diastereomeric mixture that is enriched in one oftwo epimeric C38 ketals. In certain embodiments, the synthetic routecomprises an equilibration step to enrich a compound of Formula (I) inone of two epimeric C38 ketals. In certain embodiments, theequilibration step enriches a compound of Formula (I) in the (R)-epimer.In certain embodiments, the equilibration step enriches a compound ofFormula (I) in the (R)-epimer in a range of 2:1, 3:1, 4:1, 5:1, or >5:1.In certain embodiments, the equilibration step enriches a compound ofFormula (I) in the (S)-epimer. In certain embodiments, the equilibrationstep enriches a compound of Formula (I) in the (S)-epimer in a range of2:1, 3:1, 4:1, 5:1, 10:1, or >10:1. In certain embodiments, theequilibration step comprises a Lewis acid. In certain embodiments, theequilibration step comprises a silyl Lewis acid (e.g., a silicontetrahalide or and organosilicon halide or triflate). In certainembodiments, the equilibration step comprises trimethylsilyl triflate.In certain embodiments, the equilibration step comprises a solvent. Incertain embodiments, the equilibration step comprises a halogenated(e.g., dichloromethane) or ethereal (e.g., diethylether) solvent.

In certain embodiments, preparation of C38 epi-halichondrin A comprisesan acid-mediated equilibration of the C38 ketal stereocenter ofhalichondrin A. In certain embodiments, preparation of halichondrin Acomprises an acid-mediated equilibration of the C38 ketal stereocenterof C38 epi-halichondrin A (see Scheme S1a).

In certain embodiments, preparation of C38 epi-norhalichondrin Acomprises an acid-mediated equilibration of the C38 ketal stereocenterof norhalichondrin A. In certain embodiments, preparation ofnorhalichondrin A comprises an acid-mediated equilibration of the C38ketal stereocenter of C38 epi-norhalichondrin A (see Scheme S1b).

In certain embodiments, preparation of C38 epi-homohalichondrin Acomprises an acid-mediated equilibration of the C38 ketal stereocenterof homohalichondrin A. In certain embodiments, preparation ofhomohalichondrin A comprises an acid-mediated equilibration of the C38ketal stereocenter of C38 epi-homohalichondrin A (see Scheme S1c).

In certain embodiments, preparation of C38 epi-halichondrin B comprisesan acid-mediated equilibration of the C38 ketal stereocenter ofhalichondrin B. In certain embodiments, preparation of halichondrin Bcomprises an acid-mediated equilibration of the C38 ketal stereocenterof C38 epi-halichondrin B (see Scheme S1d).

In certain embodiments, preparation of C38 epi-norhalichondrin Bcomprises an acid-mediated equilibration of the C38 ketal stereocenterof norhalichondrin B. In certain embodiments, preparation ofnorhalichondrin B comprises an acid-mediated equilibration of the C38ketal stereocenter of C38 epi-norhalichondrin B (see Scheme S1e).

In certain embodiments, preparation of C38 epi-homohalichondrin Bcomprises an acid-mediated equilibration of the C38 ketal stereocenterof homohalichondrin B. In certain embodiments, preparation ofhomohalichondrin B comprises an acid-mediated equilibration of the C38ketal stereocenter of C38 epi-homohalichondrin B (see Scheme S1f).

In certain embodiments, preparation of C38 epi-halichondrin C comprisesan acid-mediated equilibration of the C38 ketal stereocenter ofhalichondrin C. In certain embodiments, preparation of halichondrin Ccomprises an acid-mediated equilibration of the C38 ketal stereocenterof C38 epi-halichondrin C (see Scheme S1g).

In certain embodiments, preparation of C38 epi-norhalichondrin Ccomprises an acid-mediated equilibration of the C38 ketal stereocenterof norhalichondrin C. In certain embodiments, preparation ofnorhalichondrin C comprises an acid-mediated equilibration of the C38ketal stereocenter of C38 epi-norhalichondrin C (see Scheme S1h).

In certain embodiments, preparation of C38 epi-homohalichondrin Ccomprises an acid-mediated equilibration of the C38 ketal stereocenterof homohalichondrin C. In certain embodiments, preparation ofhomohalichondrin C comprises an acid-mediated equilibration of the C38ketal stereocenter of C38 epi-homohalichondrin C (see Scheme S1i).

In certain embodiments, preparation of a compound of Formula (F-1) orsalt thereof comprises joining an intermediate compound of Formula (E-1)or salt thereof and an intermediate of Formula (I-1) or salt thereof(see Scheme S2). In certain embodiments, when R^(Z4) is —CH₂OR^(Z4a) andR^(Z4a) is a protecting group, the synthetic route comprises adeprotection step. In certain embodiments, when R^(Z4a) is a silylprotecting group (e.g., t-butyldimethylsilyl), selective deprotection ofR^(Z4a) comprises a mild source of fluoride (e.g., TBAF, HF•pyridine).In certain embodiments, when R^(Z4) is —CH₂OH, the synthetic routecomprises an oxidation step. In certain embodiments, R^(Z4) is oxidizedinto an aldehyde (—CHO) under mild and selective conditions (e.g.,Dess-Martin periodinane, SO₃•pyridine, or Swern oxidation). Compounds ofFormula (E-1) are joined with a compound of Formula (I-1) underreductive coupling conditions. In certain embodiments, the conditionsused to join a compound of Formula (E-1) with a compound of Formula(I-1) comprise a transition metal (e.g., nickel or chromium). In certainembodiments, the coupling reaction is catalytic in transition metal(e.g., 2-40 mol %). In certain embodiments, the coupling reaction isstoichiometric in transition metal (e.g., 1-3 equivalents). In certainembodiments, the coupling comprises a ligand or ligated transition metalcomplex (e.g., see Scheme 4). The reaction used to join a compound ofFormula (E-1) and Formula (I-1) provides an intermediate hydroxy groupthat must be oxidized to provide a compound of Formula (F-1). In certainembodiments, the oxidation is carried out under mild and selectiveconditions (e.g., Dess-Martin periodinane, SO₃•pyridine, or Swernoxidation).

In certain embodiments, preparation of a compound of Formula (E-1) or asalt thereof comprises cyclizing an intermediate compound of Formula(D-1) or salt thereof (see Scheme S3). In certain embodiments, whereinR^(Z1) is —CO₂R^(Z1a) and R^(Z1a) is not hydrogen, and/or R^(P5) is anacyl protecting group, the synthetic route comprises a deprotection stepprior to cyclization. In certain embodiments, the deprotectionconditions comprise a hydrolysis reaction. In certain embodiments, thedeprotection conditions comprise a base (e.g., lithium, sodium, orpotassium hydroxide). In certain embodiments, the cyclization reactioncomprises a macrocyclization reagent (e.g., 2-methyl-6-nitrobenzoicanhydride (Shiina's reagent) or 2,4,6-trichlorobenzoyl chloride(Yamaguchi's reagent)).

In certain embodiments, preparation of a compound of Formula (D-1) orsalt thereof comprises joining an intermediate compound of Formula (C-1)or salt thereof and an intermediate of Formula (J-1) or salt thereof(see Scheme S4). Compounds of Formula (C-1) are joined with a compoundof Formula (J-1) under reductive coupling conditions. In certainembodiments, the conditions used to join a compound of Formula (C-1)with a compound of Formula (J-1) comprise a transition metal (e.g.,nickel or chromium). In certain embodiments, the coupling reaction iscatalytic in transition metal (e.g., 2-40 mol %). In certainembodiments, the coupling reaction is stoichiometric in transition metal(e.g., 1-3 equivalents). In certain embodiments, the coupling comprisesa ligand or ligated transition metal complex (e.g., see Scheme 4). Incertain embodiments, following the reductive coupling of a compound ofFormula (C-1) and a compound of (J-1), the synthetic route comprises anintramolecular furan cyclization reaction. In certain embodiments, thefuran cyclization reaction conditions comprise displacement of a leavinggroup with an intermediate oxyanion generated using a base (e.g., anamide or silazide base such as LDA or LiHMDS). In certain embodiments,the furan cyclization reaction conditions comprise displacement of ahalide with a hydroxyl group using one or more silver salts (e.g., Ag₂O,AgOTf). In certain embodiments, R^(Z3) is bromine and R^(Z2) ischlorine.

In certain embodiments, preparation of a compound of Formula (C-1) or asalt thereof comprises cyclizing an intermediate compound of Formula(B-1) or salt thereof (see Scheme S5). In certain embodiments, thecyclization reaction conditions comprise an intermediate epoxidation oroxidation reaction. In certain embodiments, the epoxidation or oxidationreaction comprises an organic oxidant (e.g., dimethyldioxirane ort-butyl hydroperoxide). In certain embodiments, the cyclizationconditions comprise an acid. In certain embodiments, the cyclizationconditions comprise a Bronsted acid (i.e., a source of H+). In certainembodiments, the cyclization conditions comprise an organic acid (e.g.,camphorsulfonic acid). In certain embodiments, wherein R^(X) and orR^(Y) of a compound of (D-1) are hydroxyl groups, one or both groups areoptionally protected. In certain embodiments, both R^(X) and R^(Y) areprotected as an acetal or ketal protecting group (e.g., an acetonide ora p-methoxyphenyl group).

In certain embodiments, preparation of a compound of Formula (B-1) orsalt thereof comprises joining an intermediate compound of Formula (A-1)or salt thereof and an intermediate aldehyde or salt thereof (see SchemeS6). Compounds of Formula (A-1) and the aldehyde are joined underreductive coupling conditions. In certain embodiments, the conditionsused to join a compound of Formula (A-1) with the aldehyde comprise atransition metal (e.g., nickel or chromium). In certain embodiments, thecoupling reaction is catalytic in transition metal (e.g., 2-40 mol %).In certain embodiments, the coupling reaction is stoichiometric intransition metal (e.g., 1-3 equivalents). In certain embodiments, thecoupling comprises a ligand or ligated transition metal complex (e.g.,see Scheme 4). In certain embodiments, following the reductive couplingof a compound of Formula (A-1) and the aldehyde, the synthetic routecomprises an oxidation step. In certain embodiments, the oxidation iscarried out under mild and selective conditions (e.g., Dess-Martinperiodinane, SO₃•pyridine, or Swern oxidation). In certain embodiments,following the oxidation reaction, when R^(P18) and/or R^(P19) is aprotecting group, the synthetic route comprises a selective deprotectionstep. In certain embodiments, when R^(P18) and/or R^(P19) is a silylprotecting group (e.g., t-butyldimethylsilyl), selective deprotection ofR^(P18) and/or R^(P19) comprises a mild source of fluoride (e.g., TBAF,HF•pyridine). In certain embodiments, following the optionaldeprotection reaction, the synthetic route comprises an intramolecularfuran cyclization reaction. In certain embodiments, the cyclizationreaction comprises a conjugate addition reaction proceeding through anoxyanion intermediate. In certain embodiments, the deprotection andconjugate addition reactions occur in a single step. In certainembodiments, the cyclization conditions comprise an acid or a base. Incertain embodiments, a compound of Formula (B-1) is formed as a single(E)-alkene stereoisomer. In certain embodiments, a mixture of (E)- and(Z)-alkene stereoisomers is formed (e.g., a 1:1, 2:1, 5:1, >5:1, 1:2,1:5, or >1:5 ratio of (E)- to (Z)-isomers).

In certain embodiments, preparation of compounds of Formula (II) ornorhalichondrin A or pharmaceutically acceptable salts thereof comprisescyclizing an intermediate compound of Formula (G-1) or salt thereof (seeScheme S7). In certain embodiments, when a compound of Formula (G-1) isprotected (e.g., with silyl or benzylic protecting groups), thesynthetic route comprises a deprotection step prior to cyclization. Incertain embodiments, deprotection of a compound of Formula (G-1)comprises a source of fluoride (e.g., TBAF, HF•pyridine). In certainembodiments, deprotection of a compound of Formula (G-1) comprises ahydrogenolysis (e.g., a palladium or nickel catalyst and H₂) oroxidation (e.g., DDQ) step. In certain embodiments, the cyclizationconditions comprise an acid. In certain embodiments, the cyclizationconditions comprise a Brønsted acid (i.e., a source of H+). In certainembodiments, the cyclization conditions comprise an organic acid (e.g.,PPTS). In certain embodiments, the cyclization conditions provide acompound of Formula (II) or norhalichondrin A as a single diastereomer.In certain embodiments, the cyclization conditions provide adiastereomeric mixture that is enriched in one of two epimeric C38ketals. In certain embodiments, the synthetic route comprises anequilibration step to enrich a compound of Formula (II) ornorhalichondrin A in one of two epimeric C38 ketals. In certainembodiments, the equilibration step enriches a compound of Formula (II)or norhalichondrin A in the (R)-epimer. In certain embodiments, theequilibration step enriches a compound of Formula (II) ornorhalichondrin A in the (R)-epimer in a range of 2:1, 3:1, 4:1, 5:1,or >5:1. In certain embodiments, the equilibration step enriches acompound of Formula (II) or norhalichondrin A in the (S)-epimer. Incertain embodiments, the equilibration step enriches a compound ofFormula (II) or norhalichondrin A in the (S)-epimer in a range of 2:1,3:1, 4:1, 5:1, 10:1, or >10:1. In certain embodiments, the equilibrationstep comprises a Lewis acid. In certain embodiments, the equilibrationstep comprises a silyl Lewis acid (e.g., a silicon tetrahalide or andorganosilicon halide or triflate). In certain embodiments, theequilibration step comprises trimethylsilyl triflate. In certainembodiments, the equilibration step comprises a solvent. In certainembodiments, the equilibration step comprises a halogenated (e.g.,dichloromethane) or ethereal (e.g., diethylether) solvent. In certainembodiments, when R⁷ is not hydrogen, the synthetic route comprises ahydrolysis step comprising a base (e.g., lithium, sodium, or potassiumhydroxide).

In certain embodiments, preparation of a compound of Formula (G-1) orsalt thereof comprises joining an intermediate compound of Formula (E-1)or salt thereof and an intermediate of Formula (K-1) or salt thereof(see Scheme S8). In certain embodiments, when R^(Z4) is —CH₂OR^(Z4a) andR^(Z4a) is a protecting group, the synthetic route comprises adeprotection step. In certain embodiments, when R^(Z4a) is a silylprotecting group (e.g., t-butyldimethylsilyl), selective deprotection ofR^(Z4a) comprises a mild source of fluoride (e.g., TBAF, HF•pyridine).In certain embodiments, when R^(Z4) is —CH₂OH, the synthetic routecomprises an oxidation step. In certain embodiments, R^(Z4) is oxidizedinto an aldehyde (—CHO) under mild and selective conditions (e.g.,Dess-Martin periodinane, SO₃•pyridine, or Swern oxidation). Compounds ofFormula (E-1) are joined with a compound of Formula (K-1) underreductive coupling conditions. In certain embodiments, the conditionsused to join a compound of Formula (E-1) with a compound of Formula(K-1) comprise a transition metal (e.g., nickel or chromium). In certainembodiments, the coupling reaction is catalytic in transition metal(e.g., 2-40 mol %). In certain embodiments, the coupling reaction isstoichiometric in transition metal (e.g., 1-3 equivalents). In certainembodiments, the coupling comprises a ligand or ligated transition metalcomplex (e.g., see Scheme 4). The reaction used to join a compound ofFormula (E-1) and Formula (K-1) provides an intermediate hydroxy groupthat must be oxidized to provide a compound of Formula (G-1). In certainembodiments, the oxidation is carried out under mild and selectiveconditions (e.g., Dess-Martin periodinane, SO₃•pyridine, or Swernoxidation).

In certain embodiments, preparation of compounds of Formula (III) orhomohalichondrin A or pharmaceutically acceptable salts thereofcomprises cyclizing an intermediate compound of Formula (H-1) or saltthereof (see Scheme S9). In certain embodiments, when a compound ofFormula (H-1) is protected (e.g., with silyl or benzylic protectinggroups), the synthetic route comprises a deprotection step prior tocyclization. In certain embodiments, deprotection of a compound ofFormula (G-1) comprises a source of fluoride (e.g., TBAF, HF•pyridine).In certain embodiments, deprotection of a compound of Formula (H-1)comprises a hydrogenolysis (e.g., a palladium or nickel catalyst and H₂)or oxidation (e.g., DDQ) step. In certain embodiments, the cyclizationconditions comprise an acid. In certain embodiments, the cyclizationconditions comprise a Bronsted acid (i.e., a source of H+). In certainembodiments, the cyclization conditions comprise an organic acid (e.g.,PPTS). In certain embodiments, the cyclization conditions provide acompound of Formula (III) or homohalichondrin A as a singlediastereomer. In certain embodiments, the cyclization conditions providea diastereomeric mixture that is enriched in one of two epimeric C38ketals. In certain embodiments, the synthetic route comprises anequilibration step to enrich a compound of Formula (III) orhomohalichondrin A in one of two epimeric C38 ketals. In certainembodiments, the equilibration step enriches a compound of Formula (III)or homohalichondrin A in the (R)-epimer. In certain embodiments, theequilibration step enriches a compound of Formula (III) orhomohalichondrin A in the (R)-epimer in a range of 2:1, 3:1, 4:1, 5:1,or >5:1. In certain embodiments, the equilibration step enriches acompound of Formula (III) or homohalichondrin A in the (S)-epimer. Incertain embodiments, the equilibration step enriches a compound ofFormula (III) or homohalichondrin A in the (S)-epimer in a range of 2:1,3:1, 4:1, 5:1, 10:1, or >10:1. In certain embodiments, the equilibrationstep comprises a Lewis acid. In certain embodiments, the equilibrationstep comprises a silyl Lewis acid (e.g., a silicon tetrahalide or andorganosilicon halide or triflate). In certain embodiments, theequilibration step comprises trimethylsilyl triflate. In certainembodiments, the equilibration step comprises a solvent. In certainembodiments, the equilibration step comprises a halogenated (e.g.,dichloromethane) or ethereal (e.g., diethylether) solvent.

In certain embodiments, preparation of a compound of Formula (H-1) orsalt thereof comprises joining an intermediate compound of Formula (E-1)or salt thereof and an intermediate of Formula (L-1) or salt thereof(see Scheme S10). In certain embodiments, when R^(Z4) is —CH₂OR^(Z4a)and R^(Z4a) is a protecting group, the synthetic route comprises adeprotection step. In certain embodiments, when R^(Z4a) is a silylprotecting group (e.g., t-butyldimethylsilyl), selective deprotection ofR^(Z4a) comprises a mild source of fluoride (e.g., TBAF, HF•pyridine).In certain embodiments, when R^(Z4) is —CH₂OH, the synthetic routecomprises an oxidation step. In certain embodiments, R^(Z4) is oxidizedinto an aldehyde (—CHO) under mild and selective conditions (e.g.,Dess-Martin periodinane, SO₃•pyridine, or Swern oxidation). Compounds ofFormula (E-1) are joined with a compound of Formula (L-1) underreductive coupling conditions. In certain embodiments, the conditionsused to join a compound of Formula (E-1) with a compound of Formula(L-1) comprise a transition metal (e.g., nickel or chromium). In certainembodiments, the coupling reaction is catalytic in transition metal(e.g., 2-40 mol %). In certain embodiments, the coupling reaction isstoichiometric in transition metal (e.g., 1-3 equivalents). In certainembodiments, the coupling comprises a ligand or ligated transition metalcomplex (e.g., see Scheme 4). The reaction used to join a compound ofFormula (E-1) and Formula (L-1) provides an intermediate hydroxy groupthat must be oxidized to provide a compound of Formula (H-1). In certainembodiments, the oxidation is carried out under mild and selectiveconditions (e.g., Dess-Martin periodinane, SO₃•pyridine, or Swernoxidation).

EXAMPLES

In order that the invention described herein may be more fullyunderstood, the following Examples are set forth. The synthetic andbiological examples described in this Application are offered toillustrate the compounds, pharmaceutical compositions, and methodsprovided herein and are not to be construed in any way as limiting theirscope.

Example 1 Synthesis of the Compounds

The compounds provided herein can be prepared from readily availablestarting materials using the following general methods and procedures.It will be appreciated that where typical or preferred processconditions (i.e., reaction temperatures, times, mole ratios ofreactants, solvents, pressures, etc.) are given, other processconditions can also be used unless otherwise stated. Optimum reactionconditions may vary with the particular reactants or solvents used, butsuch conditions can be determined by those skilled in the art by routineoptimization procedures.

General Procedures and Methods

NMR spectra were recorded on a Varian Inova 600 MHz, 500 MHz, or 400 MHzspectrometer. Chemical shifts are reported in parts per million (ppm).For ¹H NMR spectra (CDCl₃, C₆D₆, and/or CD₃OD), the residual solventpeak was used as the internal reference (7.26 ppm in CDCl₃; 7.16 ppm inC₆D₆; 3.31 ppm in CD₃OD), while the central solvent peak as thereference (128.0 ppm in C₆D₆; 49.0 ppm in CD₃OD) for ¹³C NMR spectra.Optical rotations were measured at 20° C. using a Perkin-Elmer 241polarimeter. IR spectra were recorded on a Bruker Alpha FT-IRspectrometer. Analytical and semi-preparative thin layer chromatography(TLC) was performed with E. Merck pre-coated TLC plates, silica gel 60F₂₅₄, layer thickness 0.25 and 1.00 mm, respectively. TLC plates werevisualized by staining with p-anisaldehyde or phosphomolybdic acidstain. Flash chromatography separations were performed on E. MerckKieselgel 60 (230-400) mesh silica gel. High performance liquidchromatography (HPLC) was carried out with Waters 1525 on a UVspectrophotometric detector (254 nm, Waters 2489) to which a 21.2×250 mmsize column (Zobrax SIL) packed with silica gel (7.0 μm) was attached.All moisture sensitive reactions were conducted under an inertatmosphere. Reaction vessels were oven-dried and allowed to cool undervacuum (1 mmHg). Reagents and solvents were commercial grade and wereused as supplied, unless otherwise noted.

For the synthesis of E-9 and Z-9 from 8 and the synthesis of β-10 fromE-9, please refer to Yamamoto, A; Ueda, A.; Bremond, P.; Tiseni, P. S.;Kishi, Y. J. Am. Chem. Soc. 2012, 134, 893.

Compound 11:

To diol (7.3 mg, 18 μmol) and p-anisaldehyde dimethyl acetal (30 μL,0.18 mmol) in DMF (0.35 mL) was added camphorsulfonic acid (CSA, 0.2 mg,0.9 μmol) at room temperature and the reaction mixture was heated at100° C. for 7 h. After cooling to room temperature, the reaction mixturewas quenched with sat. NaHCO₃ aq. and extracted with Et₂O three times.The combined organic extracts were washed with water, dried over Na₂SO₄,and concentrated under vacuum. The crude product was purified bypreparative TLC (40% EtOAc in hexanes) to yield acetal 11 (6.2 mg, 67%)as a white solid.

11: ¹H NMR (600 MHz, C₆D₆) δ: 7.35 (2H, d, J=8.8 Hz, ArH), 6.70 (1H, d,J=8.8 Hz, ArH), 6.13 (1H, s, ArCH), 4.57-4.55 (1H, m, H-8), 4.53 (ddd,J=10.0, 10.0, 4.7 Hz, H-6), 4.41 (1H, dd, J=5.3, 1.8 Hz, H-11), 4.16(1H, s, H-13), 4.06 (1H, dd, J=6.5, 5.3 Hz, H-10), 3.80-3.73 (2H, m,H-9.3), 3.30 (3H, s, CO₂CH₃), 3.21 (3H, s, ArOCH₃), 2.54 (1H, d, J=10.0Hz, H-7), 2.53 (1H, dd, J=16.1, 7.6 Hz, H-2a), 2.26-2.18 (1H, m, H-15a),2.11 (1H, dd, J=16.1, 5.0 Hz, H-2b), 2.11-2.06 (1H, m, H-15b), 2.05-1.99(1H, m, H-5a), 1.86-1.76 (2H, m, H-16a,16b), 1.40-1.34 (1H, m, H-4a),1.32-1.15 (5H, m, H-4b,5b,17a,17b,18a,18b), 0.84 (3H, t, J=7.0 Hz,CH₂CH₃). ¹³C NMR (100 MHz, C₆D₆) 6: 171.0, 161.4, 128.8 (2C), 128.6,118.8, 114.1 (2C), 109.8, 109.0, 89.8, 83.6, 79.0, 76.2, 74.7, 74.3,74.0, 68.3, 54.7, 51.0, 40.5, 34.8, 32.1, 30.7, 30.4, 23.5, 23.0, 14.1.HRMS (ESI) m/z: [M+H]⁺ calcd for C₂₈H₃₇O₁₀, 533.2381; found, 533.2381.

Compound α-10:

To a solution of Z-enone Z-9 (2.0 mg, 3.9 μmol) in acetone (0.20 mL) wasadded freshly prepared dimethyldioxirane¹⁷ (DMDO, 0.08 M in acetone, 98μL, 7.8 μmol) solution and stirred at room temperature for 30 min. Thereaction mixture was evaporated by a stream of nitrogen gas. The abovecrude material was dissolved in THF (0.20 mL) and HF•pyridine complex(70% HF content, 2.0 μL, 78 μmol) was added to the reaction at roomtemperature. After stirring for 3 h at room temperature, wet CH₂Cl₂(0.20 mL) was added to the reaction mixture, which was further stirredfor 11 h at room temperature. The reaction mixture was quenched withsat. NaHCO₃ aq. and extracted with EtOAc four times. The combinedorganic layers were dried over Na₂SO₄, filtered, and concentrated undervacuum. The residue was purified by preparative TLC (EtOAc/hexanes=2:1,developed twice) to give α-10 (0.8 mg, 50% overall yield from Z-9)exclusively.

α-10: ¹H NMR (600 MHz, CDCl₃) δ: 4.58 (1H, dd, J=4.4, 2.2 Hz), 4.41 (1H,dd, J=5.3, 4.0 Hz), 4.40 (1H, d, J=5.3 Hz), 4.33 (1H, dd, J=4.4, 4.0Hz), 4.32 (1H, ddd, J=10.3, 9.2, 5.0 Hz), 3.88 (1H, d, J=12.4 Hz),3.86-3.82 (1H, m), 3.67 (3H, s), 3.34 (1H, br s), 2.90 (1H, dd, J=9.8,2.2 Hz), 2.65 (1H, dd, J=16.1, 6.7 Hz), 2.57 (1H, d, J=12.3 Hz), 2.39(1H, dd, J=16.1, 6.2 Hz), 2.15-2.08 (1H, m), 1.95-1.87 (1H, m),1.86-1.79 (1H, m), 1.68-1.58 (2H, m), 1.52-1.23 (7H, m), 0.91 (3H, t,J=7.0 Hz). HRMS (ESI) m/z: [M+Na]⁺ calcd for C₂₀H₃₀O₉Na, 437.1782;found, 437.1796.

NOE experiment of p-anisylidene acetal 6a:

Compound 13a:

To a solution of alcohol S-1¹⁸ (653 mg, 2.38 mmol, >99% ee) in CH₂Cl₂(16 mL) was added solid NaHCO₃ (1.00 g, 11.9 mmol) and Dess-Martinperiodinane (1.51 g, 3.57 mmol) in one portion at room temperature andstirred for 1.5 h at the same temperature. The solution was quenchedwith 10 wt. % Na₂S₂O₃ aq. and sat. NaHCO₃ aq. and stirred vigorously for30 min. The aqueous phase was extracted with CH₂Cl₂ three times and thecombined organic phases were dried over Na₂SO₄. The crude material waspurified by short column chromatography on silica gel (5% EtOAc inhexanes) to give aldehyde 13a (590 mg, 91%) as colorless oil. Thismaterial was immediately used for the next step without furtherpurification.

13a: ¹H NMR (600 MHz, C₆D₆) δ: 9.13 (1H, s, CHO), 5.73-5.62 (1H, m,C19=CHH), 5.55 (1H, d, J=1.5 Hz, C19=CHH), 3.89 (1H, dddd, J=9.3, 8.5,5.3, 3.4 Hz, H-17), 2.28 (1H, ddd, J=14.6, 8.5, 1.0 Hz, H-18a), 2.22(1H, dd, J=14.6, 5.3 Hz, H-18b), 1.97 (1H, ddd, J=18.5, 8.8, 5.3 Hz,H-15a), 1.82 (1H, ddd, J=18.5, 8.8, 6.4 Hz, H-a5b), 1.62 (1H, dddd,J=14.7, 8.8, 6.4, 3.4 Hz, H-16a), 1.42 (1H, dddd, J=14.7, 9.3, 8.8, 5.3Hz, H-16b).

Compound S-6:

To a stirred solution of TBDPS-ether S-2¹⁸ (3.10 g, 8.05 mmol, >99% ee)and pyridine (3.25 mL, 40.3 mmol) in MeCN (40 mL) was added HF-pyridinecomplex (70% HF content, 1.46 mL, 56.4 mmol) at 0° C.¹⁹ After stirringfor 10 h at room temperature, the reaction mixture was carefullyquenched with sat. NaHCO₃ aq and solid NaHCO₃ at 0° C. The aqueous phasewas extracted with EtOAc three times and the combined organic phaseswere washed with 1 M HCl aq and brine, dried over Na₂SO₄, andconcentrated under reduced pressure. The residue was purified by flashcolumn chromatography on silica gel (eluent: 10% then 40% EtOAc inhexanes) to give alcohol S-3 (1.13 g, 97%) as a colorless oil.

To a solution of alcohol S-3 (1.13 g, 7.74 mmol) in CH₂Cl₂ (26 mL) at 0°C. were added pyridine (1.25 mL, 15.5 mmol), pivaloyl chloride (1.42 mL,11.6 mmol), and 4-dimethylaminopyridine (94.4 mg, 0.774 mmol) and thereaction was stirred for 5 h at room temperature. After cooling to 0°C., the reaction mixture was added MeOH (0.7 mL) and stirred for 5 minat 0° C. The resultant mixture was carefully quenched with 1 M HCl aq.at 0° C. and the aqueous layer was extracted with CH₂Cl₂ once. Thecombined organic layers were washed with brine, dried over Na₂SO₄, andconcentrated under vacuum. Purification of the residue by flash columnchromatography on silica gel (eluent: 5% EtOAc in hexanes) affordedpivaloyl ester S-4 (1.60 g, 90%) as a colorless oil.

To a solution of alkyne S-4 (800 mg, 3.48 mmol) in CH₂Cl₂ (13.9 mL) wasdropped B-bromo-9-BBN²⁰ solution (1 M in CH₂Cl₂, 10.4 mL, 10.4 mmol) at0° C. and stirred for 7 h at the same temperature prior to the additionof AcOH (1.19 mL, 20.9 mmol). After stirring at room temperature for 50min, the reaction was cooled to 0° C. and carefully added 3 M NaOH aq.(8.35 mL, 25.1 mmol) and H₂O₂ solution (30% in H₂O, 11.8 mL, 104 mmol),and further stirred for 10 min at 0° C. The reaction mixture wasquenched with 10 wt. % Na₂S₂O₃ aq. The aqueous phase was extracted withCH₂Cl₂ three times and the combined organic extracts were washed with 10wt. % Na₂S₂O₃ and sat. NaHCO₃ aq. and dried over sodium sulfate, andconcentrated under vacuum. The residue was purified by flash columnchromatography on silica gel eluted with 1% Et₂O in hexanes to givebromoalkene S-5 (1.02 g, 94%) as colorless oil.

To a solution of bromoalkene S-5 (1.02 g, 3.28 mmol) in CH₂Cl₂ (33 mL)at −78° C. was added DIBAL-H solution (1 M in toluene, 6.56 mL, 6.56mmol) and stirred for 30 min at the same temperature. The reactionmixture was carefully quenched by adding Na₂SO₄.10H₂O. The resultantwhite suspension was filtered through a pad of Celite (1 cm) and thefilter cake was washed with CH₂Cl₂. After removal of the solvent, theresidue was purified by flash column chromatography on silica gel (10%then 20% EtOAc in hexanes) to provide alcohol S-6 (704 mg, 95%) ascolorless oil.

S-6: [α]²⁰ _(D)+4.6 (c 0.57, CHCl₃). ¹H NMR (500 MHz, C₆D₆) δ: 5.29 (1H,d, J=2.0 Hz, C19=CHH), 5.26 (1H, ddd, J=2.0, 2.0, 1.0 Hz, C19=CHH), 4.08(1H, dddd, J=9.0, 8.3, 4.9, 3.4 Hz, H-17), 3.17 (2H, td, J=5.9, 5.4 Hz,H-14), 2.44 (1H, dd, J=14.6, 8.3 Hz, H-18a), 2.35 (1H, dd, J=14.6, 4.9Hz, H-18b), 1.58-1.45 (2H, m), 1.45-1.34 (1H, m), 1.35-1.25 (1H, m),0.38 (1H, t, J=5.4 Hz, OH). ¹³C NMR (125 MHz, C₆D₆) δ: 129.9, 120.0,61.8, 60.1, 50.1, 34.1, 29.6. HRMS (ESI) m/z: [M+Na]⁺ calcd forC₇H₁₂OBrClNa, 248.9652; found, 248.9653.

Compound S-7:

To a solution of alcohol S-6 (2.2 mg, 9.7 μmol) in CH₂Cl₂ (0.10 mL) wereadded 4-acetylphenyl isocyanate (1.9 mg, 11.6 μmol) and4-dimethylaminopyridine (0.2 mg, 2 μmol) at room temperature. Thereaction mixture was stirred for 1 h at the same temperature prior toquenching with sat. NaHCO₃ aq. The aqueous phase was extracted withEtOAc twice and the combined organic phases were dried (Na₂SO₄) andconcentrated in vacuo. The residue was purified by preparative TLC (30%EtOAc in hexanes) to give urethane S-7 (3.2 mg, 86%) as a white solid.Racemic sample of S-7 was also prepared from racemic alcohol of compound8 in footnote reference 3 via chlorination of secondary alcohol followedby above 5 step protocol. The optical purity of urethane S-7 wasdetermined as >99% ee by HPLC analysis (Chart S1). HPLC Condition.Column: chiralpak OJ-H; solvent system:hexanes/i-propanol/diethylamine=85%/15%/0.1%; flow rate=1.0 mL/min;detector=UV at 277 nm; retention time: 40.4 and 37.0 min for (R)- and(S)-enantiomers, respectively.

The optical purity of alcohol S-6 was determined as >99% ee by HPLCanalysis (OJ-H chiral column) of its 4-acetylphenylurethane derivativeS-7 prepared from S-6.

Compound 13b:

To a solution of alcohol S-6 (701 mg, 3.09 mmol) in CH₂Cl₂ (31 mL) wereadded NaHCO₃ (2.60 g, 30.9 mmol) and Dess-Martin periodinane (1.97 g,4.64 mmol) at room temperature and stirred for 1 h at room temperature.The reaction mixture was quenched with 10 wt. % Na₂S₂O₃ and sat. NaHCO₃aq. and vigorously stirred for 30 min. The aqueous phase was extractedwith CH₂Cl₂ three times and the combined organic phases were washed with10 wt. % Na₂S₂O₃ and sat. NaHCO₃ aq. and then dried over sodium sulfate.After removal of the solvent, the crude material was purified by flashchromatography on short silica gel column (5% EtOAc in hexanes) to givealdehyde 13b (635 mg, 91%) as colorless oil. This material wasimmediately used for the next step without further purification.

13b: ¹H NMR (500 MHz, C₆D₆) δ: 9.12 (1H, s, CHO), 5.33-5.24 (1H, m,C19=CHH), 5.24-5.18 (1H, m, C19=CHH), 3.92 (1H, dddd, J=9.2, 8.3, 5.4,3.4 Hz, H-17), 2.33 (1H, dd, J=14.6, 8.3 Hz, H-18a), 2.23 (1H, dd,J=14.6, 5.4 Hz, H-18b), 1.97 (1H, ddd, J=18.6, 8.8, 5.4 Hz, H-15a), 1.81(1H, ddd, J=18.6, 8.8, 6.3 Hz, H-15b), 1.62 (1H, dddd, J=14.6, 8.8, 6.3,3.4 Hz, H-16a), 1.41 (1H, dddd, J=14.6, 9.2, 8.8, 5.4 Hz, H-16b).

Compound 14a:

To a mixture of CrCl₂ (41.6 mg, 0.338 mmol), (R)-sulfonamide ligand I²¹(116 mg, 0.372 mmol), and proton sponge (79.6 mg, 0.372 mmol) in a glovebox was added MeCN (4.2 mL) and stirred for 1 h at room temperature. Ina separate flask, iodide 12⁵ (1.30 g, 1.69 mmol), aldehyde 13a (552 mg,2.03 mmol), NiCl₂.2,9-dimethyl-1,10-phenanthroline complex (NiCl₂-DMP,0.055 mg, 0.00017 mmol, doped in LiCl), LiCl (143 mg, 3.38 mmol), Mn(186 mg, 3.38 mmol), Cp₂ZrCl₂ (493 mg, 1.69 mmol) were mixed togetherand the Cr-complex solution was transferred to the flask. AdditionalNiCl₂.DMP (0.055 mg each, 0.00017 mmol) was added after 4 and 8 h andthe reaction was further stirred for 12 h at room temperature. Thereaction was removed from the glove box and diluted with EtOAc. Florisilwas added and the suspension was stirred vigorously for 30 min. Theresultant suspension was filtered through short pad of silica gel (1 cm,EtOAc) and concentrated. The crude material was purified by flashchromatography on silica gel (5% then 15% EtOAc in hexanes) to givealcohol S-8 (1.32 g, 85%).

To a solution of propargylic alcohol S-8 (1.32 g, 1.44 mmol) in CH₂Cl₂(28 mL) were added NaHCO₃ (1.21 g, 14.4 mmol) and Dess-Martinperiodinane (916 mg, 2.16 mmol) at room temperature and the reactionmixture was stirred for 1 h at room temperature. The reaction wasquenched with 10 wt. % Na₂S₂O₃ aq. and sat. NaHCO₃ aq. and vigorouslystirred for 30 min. The aqueous phase was extracted with CH₂Cl₂ threetimes and the combined organic phases were dried over Na₂SO₄ andconcentrated under vacuum. The residue was purified by flash columnchromatography on silica gel (5% EtOAc in hexanes) to provide ynone 14a(1.28 g, 97%) as colorless oil.

14a: [α]²⁰ _(D)−33.8 (c 1.0, CHCl₃). ¹H NMR (600 MHz, C₆D₆) δ: 5.72 (1H,d, J=2.9 Hz, H-11), 5.70 (1H, ddd, J=1.5, 1.2, 1.0 Hz, C19=CHH), 5.55(1H, d, J=1.5 Hz, C19=CHH), 4.42 (1H, ddd, J=9.9, 9.4, 4.8 Hz, H-6),4.22 (1H, dd, J=6.6, 2.9 Hz, H-10), 4.16 (1H, dd, J=2.2, 2.1 Hz, H-8),4.00 (1H, dddd, J=9.8, 8.2, 5.3, 3.2 Hz, H-17), 3.88 (1H, dd, J=6.6, 2.2Hz, H-9), 3.85-3.76 (1H, m, H-3), 3.36 (3H, s, OCH₃), 2.90 (1H, dd,J=9.4, 2.1 Hz, H-7), 2.75 (1H, ddd, J=17.9, 8.8, 5.3 Hz, H-15a), 2.59(1H, ddd, J=17.9, 8.8, 6.4 Hz, H-15b), 2.48 (1H, dd, J=15.2, 8.2 Hz,H-2a), 2.33 (1H, ddd, J=14.6, 8.2, 1.0 Hz, H-18a), 2.29 (1H, ddd,J=14.6, 5.3, 1.2 Hz, H-18b), 2.29-2.23 (1H, m, H-5a), 2.13 (1H, dd,J=15.2, 5.0 Hz, H-2b), 1.90 (1H, dddd, J=14.7, 8.8, 6.4, 3.2 Hz, H-16a),1.66 (1H, dddd, J=14.7, 9.8, 8.8, 5.3 Hz, H-16b), 1.51-1.37 (3H, m,H-4a, 4b, 5b), 1.13 (9H, s, SiC(CH₃)₃), 1.06 (9H, s, SiC(CH₃)₃), 0.90(9H, s, SiC(CH₃)₃), 0.44 (3H, s, SiCH₃), 0.32 (3H, s, SiCH₃), 0.32 (3H,s, SiCH₃), 0.27 (3H, s, SiCH₃), 0.05 (6H, s, 2 x SiCH₃). ¹³C NMR (125MHz, C₆D₆) δ: 184.5, 170.9, 128.9, 105.9, 92.4, 86.8, 82.2, 79.3, 74.6,73.0, 70.1, 65.2, 64.0, 60.3, 53.4, 51.1, 42.2, 40.8, 31.0, 30.9, 29.3,26.6 (3C), 26.4 (3C), 26.3 (3C), 19.1, 18.9, 18.4, −3.2, −3.6, −3.8,−4.4, −4.46, −4.51. HRMS (ESI) m/z: [M+H]⁺ calcd for C₃₉H₇₁ClIO₈Si₃,913.3184; found, 913.3212.

Compounds E-15a and Z-15a:

To a 0° C. solution of ynone 14a (513 mg, 0.561 mmol) in pyridine (4.53mL, 56.1 mmol) and MeCN (11.2 mL) in a plastic vial was addedHF-pyridine complex (70% HF content, 1.45 mL, 56.1 mmol) and stirred atroom temperature for 16 h. The reaction was cooled to 0° C. andcarefully neutralized with sat. NaHCO₃ aq. and solid NaHCO₃. The mixturewas extracted with EtOAc four times, dried over Na₂SO₄, and concentratedunder reduced pressure. ¹H NMR of the crude material showed 10:1 ratioof E-15a and Z-5a. The crude material was purified by flash columnchromatography on silica gel eluted with 10%, 17.5% (for E-15a), andthen 30% (for Z-15a) EtOAc in hexanes to afford E-15a (238 mg, 62%) andZ-15a (23.0 mg, 6%). Since these E- and Z-compounds are in equilibrium,purified material E-15a was immediately used for the next step withoutfurther purification.

E-15a: [α]²⁰ _(D)−125.3 (c 0.12, CHCl₃). ¹H NMR (600 MHz, C₆D₆) δ: 5.75(1H, d, J=0.8 Hz, H-13), 5.73 (1H, ddd, J=1.5, 1.2, 0.9 Hz, C19=CHH),5.57 (1H, d, J=1.5 Hz, C19=CHH), 5.10 (1H, ddd, J=7.9, 7.3, 0.8 Hz,H-11), 4.86 (1H, d, J=7.3 Hz, C11-OH), 4.30 (1H, ddd, J=10.5, 9.8, 4.8Hz, H-6), 4.08 (1H, dddd, J=9.8, 7.6, 5.9, 3.2 Hz, H-17), 3.91 (1H, dd,J=4.7, 1.6 Hz, H-8), 3.85 (1H, dd, J=8.5, 7.9 Hz, H-10), 3.78 (1H, dd,J=8.5, 4.7 Hz, H-9), 3.68 (1H, dddd, J=10.9, 8.8, 4.3, 1.9 Hz, H-3),3.39 (3H, s, OCH₃), 2.54 (1H, dd, J=9.8, 1.6 Hz, H-7), 2.53 (1H, ddd,J=17.1, 8.5, 5.3 Hz, H-15a), 2.42-2.34 (3H, m, H-15b, 18a, 18b), 2.33(1H, dd, J=15.5, 8.8 Hz, H-2a), 2.04-1.96 (3H, m, H-2b, 5a, 16a), 1.73(1H, dddd, J=14.6, 9.8, 8.5, 5.3 Hz, H-16b), 1.27-1.15 (2H, m, H-4a,5b), 1.02 (9H, s, SiC(CH₃)₃), 0.98-0.91 (1H, m, H-4b), 0.19 (3H, s,SiCH₃), 0.16 (3H, s, SiCH₃). ¹³C NMR (125 MHz, C₆D₆) δ: 198.0, 176.5,170.9, 128.8, 106.3, 102.3, 77.4, 77.1, 74.7, 71.1, 69.7, 67.7, 66.0,60.9, 53.6, 51.1, 40.5, 40.2, 31.9, 30.1, 29.9, 26.0 (3C), 18.7, −4.4,−4.6. HRMS (ESI) m/z: [M+H]⁺ calcd for C₂₇H₄₃ClIO₈Si, 685.1455; found,685.1455.

Compounds 16 and 6a:

To a solution of enone E-15a (238 mg, 0.347 mmol) in acetone (11 mL) at0° C. was dropped DMDO solution (0.08 M in acetone, 8.7 mL, 0.69 mmol)over 30 min. The reaction was further stirred for 30 min at 0° C. andthe solvent was removed by a stream of nitrogen to give crude epoxideS-9.

The residue S-9 was dissolved in CH₂Cl₂ (6.9 mL) and added CSA in wetCH₂Cl₂ solution (1 mg/mL, 0.35 mL) at room temperature.

After evaporation of the solvent, the obtained triol S-10 was dissolvedin MeCN (6.9 mL) and added HF.pyridine (70% HF content, 0.90 mL, 35mmol) at room temperature. The reaction mixture was stirred for 2 h atroom temperature and then carefully quenched with sat. NaHCO₃ aq. andsolid NaHCO₃ at 0° C. The mixture was extracted with EtOAc four timesand the combined organic phases were dried over Na₂SO₄ and concentratedunder vacuum. Purification of the crude material by flash columnchromatography on silica gel (40% then 60% EtOAc in hexanes) gavepolycyclic ketal S-11 (128 mg, 63%) as white foam.

To a solution of diol S-11 in CH₂Cl₂ (20 mL) were added p-anisaldehydedimethyl acetal (0.348 mL, 2.05 mmol) and p-Ts0H.H₂O (1.5 mg, 8.2 μmol)at room temperature. The pale violet solution was stirred for 3 h atroom temperature and quenched with Et₃N (0.1 mL, turned to colorlessclear solution) and sat. NaHCO₃ aq. The aqueous phase was extracted withEtOAc three times and the combined organic phases were dried over Na₂SO₄and concentrated under vacuum. The residue was purified by flash columnchromatography on silica gel (CH₂Cl₂ to remove excess dimethyl acetal,30% EtOAc in hexanes to collect desired product, then 60% EtOAc inhexanes to recover starting material) to provide a mixture ofanisylidene acetal 6a and 16 (204 mg , 71%, 2:1) along with recovery ofstarting material S-11 (47.5 mg, 20% rsm). These iodoolefin 6a andterminal acetylene 16 was separated by HPLC under the followingconditions; column: Zobrax SIL, flow rate: 5 mL/min, eluent: 30% EtOAcin hexanes: retention time, 41.3 min for 6a and 48.0 min for 16.

6a: [α]²⁰ _(D)−50.6 (c 1.00, CHCl₃). ¹H NMR (600 MHz, C₆D₆) δ 7.34 (2H,d, J=8.8 Hz, ArH), 6.70 (2H, d, J=8.8 Hz, ArH), 6.11 (1H, s, ArCH), 5.77(1H, d, J=1.2 Hz, C19=CHH), 5.62 (1H, d, J=0.9 Hz, C19=CHH), 4.49 (1H,dd, J=3.4, 1.2 Hz, H-8), 4.41-4.35 (1H, m, H-6), 4.37 (1H, dd, J=5.3,1.2 Hz, H-11), 4.16 (1H, dddd, J=9.4, 8.5, 5.0, 3.5 Hz, H-17), 4.05 (1H,s, H-13), 4.02 (1H, dd, J=6.4, 5.3 Hz, H-10), 3.75 (1H, ddd, J=6.4, 3.4,1.2 Hz, H-9), 3.74-3.69 (1H, m, H-3), 3.32 (3H, s, CO₂CH₃), 3.22 (3H, s,ArOCH₃), 2.57-2.48 (3H, m, H-2a, 7, 18a), 2.48-2.44 (1H, m, H-15a), 2.44(1H, dd, J=15.2, 8.5 Hz, H-18b), 2.24 (1H, dddd, J=13.5, 9.4, 6.7, 4.1Hz, H-16a), 2.15 (1H, dd, J=15.8, 5.0 Hz, H-2b), 2.19-2.11 (1H, m,H-16b), 2.07 (1H, ddd, J=13.2, 11.4, 4.1 Hz, H-15b), 2.04-1.98 (1H, m,H-5a), 1.38-1.32 (1H, m, H-4a), 1.30-1.16 (2H, m, H-4b, 5b). ¹³C NMR(125 MHz, C₆D₆) δ: 170.9, 161.4, 128.7 (3C), 128.4, 118.7, 114.1 (2C),109.2, 109.0, 106.7, 89.7, 83.7, 78.7, 76.2, 74.7, 74.2, 73.9, 68.3,61.1, 54.7, 53.2, 51.1, 40.5, 31.7, 31.4, 30.6, 30.4. HRMS (ESI) m/z:[M+H]⁺ calcd for C₂₉H₃₅ClIO₁₀, 705.0958; found, 705.0954.

16: ¹H NMR (600 MHz, C₆D₆) δ: 7.36-7.29 (2H, m, ArH), 6.73-6.66 (2H, m,ArH), 6.09 (1H, s, ArCH), 4.46 (1H, dd, J=3.5, 1.5 Hz, H-8), 4.37 (1H,ddd, J=10.0, 10.0, 4.7 Hz, H-6), 4.34 (1H, dd, J=5.3, 1.5 Hz, H-11),4.02 (1H, s, H-13), 4.01-3.94 (2H, m, H-10,17), 3.77-3.73 (1H, m, H-3),3.72 (1H, ddd, J=6.4, 3.5, 1.5 Hz, H-9), 3.31 (3H, s, CO₂CH₃), 3.22 (3H,s, ArOCH₃), 2.55 (1H, dd, J=15.8, 7.9 Hz, H-2a), 2.50-2.42 (4H, m,H-7,15a,16a,18a), 2.39 (1H, ddd, J=17.0, 6.4, 2.6 Hz, H-16b), 2.16 (1H,dd, J=15.8,4.7 Hz, H-2b), 2.15-2.07 (2H, m, H-15b,18b), 2.02-1.96 (1H,m, H-5a), 1.90 (1H, t, J=2.6 Hz, CCH), 1.39-1.33 (1H, m, H-4a),1.29-1.22 (2H, m, H-4b,5b). ¹³C NMR (100 MHz, C₆D₆) δ: 171.0, 161.4,128.7 (2C), 128.4, 118.7, 114.1 (2C), 109.10, 109.07, 89.8, 83.7, 80.1,78.7, 76.2, 74.6, 74.1, 73.9, 71.7, 68.3, 59.9, 54.7, 51.1, 40.6, 31.5,31.4, 30.6, 30.3, 28.8. HRMS (ESI) m/z: [M+Na]⁺ calcd for C₂₉H₃₃ClO₁₀Na,599.1654; found, 599.1665.

Compound 14b:

To a mixture of CrCl₂ (47.0 mg, 0.382 mmol), (R)-sulfonamide ligand I(131 mg, 0.420 mmol), and proton sponge (89.9 mg, 0.420 mmol) in a glovebox was added MeCN (4.8 mL) and stirred for 1 h at room temperature. Ina separate flask, iodide 12 (1.47 g, 1.91 mmol), aldehyde 13b (518 mg,2.29 mmol), NiCl₂-2,9-diethyl-1,10-phenanthroline complex (NiCl₂.DEP,0.070 mg, 0.00019 mmol, doped in LiCl), LiCl (162 mg, 3.82 mmol), Mn(210 mg, 3.82 mmol), Cp₂ZrCl₂ (558 mg, 1.91 mmol) were mixed togetherand the Cr-complex solution was transferred to the flask. AdditionalNiCl₂.DEP (0.070 mg each, 0.00019 mmol) was added after 7 and 19 h andthe reaction was further stirred for 2 h at room temperature. Thereaction was removed from the glove box and diluted with EtOAc. Florisilwas added and the suspension was stirred vigorously for 30 min. Theresultant suspension was filtered through short pad of silica gel (1 cm,EtOAc) and concentrated. The crude material was purified by flashchromatography on silica gel (5% then 15% EtOAc in hexanes) to givealcohol S-12 (1.51 g, 91%).

To a solution of propargylic alcohol S-12 (1.51 g, 1.74 mmol) in CH₂Cl₂(35 mL) were added NaHCO₃ (1.46 g, 17.4 mmol) and Dess-Martinperiodinane (1.11 g, 2.61 mmol) at room temperature and the reactionmixture was stirred for 1 h at room temperature. The reaction wasquenched with 10 wt. % Na₂S₂O₃ aq. and sat. NaHCO₃ aq. and vigorouslystirred for 30 min. The aqueous phase was extracted with CH₂Cl₂ threetimes and the combined organic phases were dried over Na₂SO₄ andconcentrated under vacuum. The residue was purified by flash columnchromatography on silica gel (5% EtOAc in hexanes) to provide ynone 14b(1.44 g, 96%) as colorless oil.

14b: [α]²⁰ _(D)−31.8 (c 0.50, CHCl₃). ¹H NMR (600 MHz, C₆D₆) δ: 5.72(1H, d, J=2.9 Hz, H-11), 5.27 (1H, d, J=1.8 Hz, C19=CHH), 5.24 (1H, ddd,J=1.8, 1.1, 0.7 Hz, C19=CHH), 4.41 (1H, ddd, J=9.9, 9.5, 4.8 Hz, H-6),4.21 (1H, dd, J=6.6, 2.9 Hz, H-10), 4.16 (1H, dd, J=2.2, 2.1 Hz, H-8),4.03 (1H, dddd, J=9.8, 8.5, 5.2, 3.2 Hz, H-17), 3.88 (1H, dd, J=6.6, 2.2Hz, H-9), 3.84-3.77 (1H, m, H-3), 3.36 (3H, s, OCH₃), 2.90 (1H, dd,J=9.5, 2.1 Hz, H-7), 2.75 (1H, ddd, J=17.9, 8.8, 5.0 Hz, H-15a), 2.59(1H, ddd, J=17.9, 8.8, 6.4 Hz, H-15b), 2.48 (1H, dd, J=15.2, 8.5 Hz,H-2a), 2.38 (1H, ddd, J=14.9, 8.5, 0.7 Hz, H-18a), 2.30 (1H, ddd,J=14.9, 5.2, 1.1 Hz, H-18b), 2.28-2.24 (1H, m, H-5a), 2.12 (1H, dd,J=15.2, 4.7 Hz, H-2b), 1.90 (1H, dddd, J=14.8, 8.8, 6.4, 3.2 Hz, H-16a),1.65 (1H, dddd, J=14.8, 9.8, 8.8, 5.0 Hz, H-16b), 1.52-1.38 (3H, m,H-4a, 4b, 5b), 1.13 (9H, s, SiC(CH₃)₃), 1.06 (9H, s, SiC(CH₃)₃), 0.90(9H, s, SiC(CH₃)₃), 0.43 (3H, s, SiCH₃), 0.32 (3H, s, SiCH₃), 0.32 (3H,s, SiCH₃), 0.27 (3H, s, SiCH₃), 0.05 (6H, s, 2 x SiCH₃). ¹³C NMR (125MHz, C₆D₆) δ: 184.5, 170.9, 129.3, 120.1, 92.4, 86.8, 82.2, 79.3, 74.6,73.0, 70.9, 65.2, 64.0, 59.1, 51.1, 50.0, 42.2, 40.8, 31.1, 30.9, 29.2,26.6 (3C), 26.4 (3C), 26.3 (3C), 19.1, 18.9, 18.4, −3.2, −3.6, −3.8,−4.3, −4.4, −4.5. HRMS (ESI) m/z: [M+Na]⁺ calcd for C₃₉F1₇₀BrC10₈Si₃Na,887.3143; found, 887.3113.

Compounds E-15b and Z-15b:

To a 0° C. solution of ynone 14b (1.34 g, 1.55 mmol) in pyridine (12.5mL, 155 mmol) and MeCN (31 mL) in a plastic vial was added HF-pyridinecomplex (70% HF content, 4.03 mL, 155 mmol) and stirred for 16 h at roomtemperature. The reaction was cooled to 0° C. and carefully neutralizedwith sat. NaHCO₃ aq. and solid NaHCO₃. The mixture was extracted withEtOAc four times, dried over Na₂SO₄, and concentrated under reducedpressure. ¹H NMR of the crude material showed 10:1 ratio of E-15b andZ-15b. The crude material was purified by flash column chromatography onsilica gel eluted with 10%, 17.5% (for E-15b), and then 30% (for Z-15b)EtOAc in hexanes to afford E-15b (581 mg, 59%) and Z-15b (59.1 mg, 6%).Since these two compounds are in equilibrium, purified material, E-15bwas immediately used for the next step without further purification.

E-15b: [α]²⁰ _(D)−135.2 (c 0.63, CHCl₃). ¹H NMR (600 MHz, C₆D₆) δ: 5.75(1H, d, J=1.2 Hz, H-13), 5.29 (1H, d, J=1.8 Hz, C19=CHH), 5.28 (1H, ddd,J=1.8, 1.2, 0.7 Hz, C19=CHH), 5.10 (1H, ddd, J=7.6, 7.4, 1.2 Hz, H-11),4.85 (1H, d, J=7.6 Hz, C11-OH), 4.29 (1H, ddd, J=10.3, 10.0, 4.7 Hz,H-6), 4.12 (1H, dddd, J=9.8, 8.2, 5.3, 3.5 Hz, H-17), 3.91 (1H, dd,J=4.7, 1.8 Hz, H-8), 3.85 (1H, dd, J=8.6, 7.4 Hz, H-10), 3.77 (1H, dd,J=8.6, 4.7 Hz, H-9), 3.68 (1H, dddd, J=11.1, 8.8, 4.2, 2.1 Hz, H-3),3.39 (3H, s, OCH₃), 2.54 (1H, dd, J=10.0, 1.8 Hz, H-7), 2.54 (1H, ddd,J=17.0, 8.2, 5.3 Hz, H-15a), 2.44 (1H, ddd, J=14.6, 8.2, 0.7 Hz, H-18a),2.37 (1H, ddd, J=14.6, 5.3, 1.2 Hz, H-18b), 2.37 (1H, ddd, J=17.0, 8.2,6.0 Hz, H-15b), 2.33 (1H, dd, J=15.2, 8.8 Hz, H-2a), 2.04-1.97 (3H, m,H-2b, 5a, 16a), 1.73 (1H, dddd, J=14.6, 9.8, 8.2, 5.3 Hz, H-16b),1.27-1.15 (2H, m, H-4a, 5b), 1.01 (9H, s, SiC(CH₃)₃), 0.98-0.90 (1H, m,H-4b), 0.18 (3H, s, SiCH₃), 0.15 (3H, s, SiCH₃). ¹³C NMR (125 MHz, C₆D₆)δ 197.9, 176.4, 170.9, 129.7, 120.0, 102.3, 77.3, 77.0, 74.7, 71.2,69.6, 67.7, 66.0, 59.8, 51.1, 50.1, 40.5, 40.2, 32.1, 30.1, 29.9, 26.0(3C), 18.7, −4.4, −4.6. HRMS (ESI) m/z: [M+H]⁺ calcd for C₂₇H₄₃BrClO₈Si,637.1594; found, 637.1564.

Compound S-15:

To an acetone (18 mL) solution of E-15b (581 mg, 0.911 mmol) in aplastic vial was added DMDO solution (0.08 M in acetone, 22.8 mL, 1.82mmol) in one portion at room temperature. After stirring for 15 min atroom temperature, the reaction mixture was concentrated by a stream ofnitrogen in a fume hood to give epoxide S-13.

The crude material S-13 was dissolved in CH₂Cl₂ (9.0 mL) and treatedwith CSA in wet CH₂Cl₂ solution (1 mg/mL, 2.0 mL) at room temperature.After stirring for 5 min at room temperature, the solvent was removed toafford triol S-14.

The crude product S-14 was dissolved in MeCN (18 mL) and HF•pyridine(70% HF content, 2.37 mL, 91.1 mmol) was added to the solution at roomtemperature. The reaction mixture was stirred for 3 h at roomtemperature and then carefully quenched with sat. NaHCO₃ aq. and solidNaHCO₃ at 0° C. The mixture was extracted with EtOAc four times and thecombined organic phases were dried over Na₂SO₄ and concentrated undervacuum. Purification of the residue by flash column chromatography onsilica gel (40% then 80% EtOAc in hexanes) gave polycyclic ketal S-15(450 mg, 92% in 3 steps) as a pale yellow amorphous.

To a solution of diol S-15 (450 mg, 0.835 mmol) in CH₂Cl₂ (84 mL) wereadded p-anisaldehyde dimethyl acetal (0.71 mL, 4.18 mmol) and p-TsOH(3.2 mg, 16.7 μmol) at room temperature. The mixture was stirred for 1 hat room temperature and during that time the reaction color turned toclear pink. The reaction was quenched with triethylamine (0.1 mL, pinkcolor disappeared) and sat. NaHCO₃ aq. The organic phase was separatedand the aqueous phase was extracted with EtOAc three times. Combinedorganic phases were dried over Na₂SO₄ and concentrated under vacuum. Thecrude material was purified by flash column chromatography on silica gel(CH₂Cl₂ to remove excess reagent, 20%, 30% for desired product, 40%,then 60% for starting material) to afford acetal 6b (416 mg, 76%) as awhite solid along with recovery of starting material S-15 (53.0 mg, 12%rsm).

6b: Mp 128-130° C. [α]²⁰ _(D)−48.4 (c 0.50, CHCl₃). ¹H NMR (600 MHz,C₆D₆) δ: 7.33 (2H, d, J=8.8 Hz, ArH), 6.70 (2H, d, J=8.8 Hz, ArH), 6.11(1H, s, ArCH), 5.34 (1H, d, J=1.8 Hz, C19=CHH), 5.32-5.30 (1H, m,C19=CHH), 4.48 (1H, dd, J=3.4, 1.5 Hz, H-8), 4.42-4.35 (1H, m, H-6),4.36 (1H, dd, J=5.4, 1.3 Hz, H-11), 4.18 (1H, dddd, J=9.1, 7.3, 5.1, 5.1Hz, H-17), 4.05 (1H, s, H-13), 4.02 (1H, dd, J=6.5, 5.4 Hz, H-10), 3.74(1H, ddd, J=6.5, 3.4, 1.3 Hz, H-9), 3.74-3.69 (1H, m, H-3), 3.31 (3H, s,CO₂CH₃), 3.21 (3H, s, ArOCH₃), 2.57-2.44 (5H, m, H-2a, 7, 15a, 18a,18b), 2.25 (1H, dddd, J=13.8, 9.1, 6.9, 4.1 Hz, H-16a), 2.15 (1H, dd,J=15.8, 5.0 Hz, H-2b), 2.16-2.10 (1H, m, H-16b), 2.07 (1H, ddd, J=13.5,11.4, 4.1 Hz, H-15b), 2.04-1.99 (1H, m, H-5a), 1.37-1.32 (1H, m, H-4a),1.30-1.17 (2H, m, H-4b, 5b). ¹³C NMR (125 MHz, C₆D₆) 6: 170.9, 161.4,129.9, 128.8 (2C), 128.4, 120.0, 118.7, 114.2 (2C), 109.1, 108.9, 89.7,83.7, 78.7, 76.2, 74.6, 74.1, 73.8, 68.3, 60.1, 54.8, 51.2, 49.7, 40.4,31.7, 31.5, 30.6, 30.3. HRMS (ESI) m/z: [M+H]⁺ calcd for C₂₉H₃₅BrClO₁₀,657.1097; found, 657.1115.

The precursor of aldehyde 7, alcohol S-16, was synthesized via twodifferent routes as described in Scheme 8.

Route 1, Compound S-16:

To a solution of alcohol S-17²² (959 mg, 1.29 mmol) in CH₂Cl₂ (13 mL)were added 3,4-dihydro-2H-pyran (DHP, 0.353 mL, 3.87 mmol) andp-TsOH.H₂O (16 mg, 0.064 mmol) at room temperature and stirred for 30min. The reaction mixture was quenched with sat. NaHCO₃ aq., extractedwith CH₂Cl₂ three times, and dried over Na₂SO₄. Removal of the solventgave crude material S-20, which was used for the next step withoutfurther purification.

To a solution of dibenzoate S-20 in CH₂Cl₂ at −78° C. was added DIBAL-Hsolution (1 M in toluene, 5.16 mL, 5.16 mmol) and stirred for 30 min atthe same temperature. The reaction was carefully quenched withNa₂SO₄.H₂O and warmed up to room temperature. The CH₂Cl₂ solution wasdirectly passed through a short plug of silica gel (15 g, 2 cm), whichwas first washed with 20%, 30%, and 40%, EtOAc in hexanes (80, 80, and40 mL, respectively), and the desired material was eluted with 0% and10% MeOH in EtOAc (30 and 250 mL, respectively). The solvent was removedin vacuo to afford the diol S-21 as a colorless oil.

This material was used for the next step without further purification.To a mixture of diol S-21 and 2,6-lutidine (0.900 mL, 7.74 mmol) inCH₂Cl₂ (13 mL) was dropped TBSOTf (0.888 mL, 3.87 mmol) at −78° C. andstirred for 1 h at the same temperature. The reaction mixture wasquenched with sat. NaHCO₃ aq. and then warmed to room temperature. Theaqueous phase was extracted with EtOAc three times and the combinedorganic phases were washed with 1 M HCl and sat. NaHCO₃ aq., dried overNa₂SO₄, and concentrated under reduced pressure to give S-22.

To a solution of crude MPM-ether S-22 in wet CH₂Cl₂ (26 mL) was added2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ, 586 mg, 2.58 mmol) in oneportion at room temperature and the resultant dark brown solution wasvigorously stirred for 20 min at room temperature. The reaction mixturewas quenched with 10 wt. % Na₂S₂O₃ aq. and sat. NaHCO₃ aq., extractedwith CH₂Cl₂ twice, and dried over Na₂SO₄. The solution was passedthrough a short silica gel column (25 g, 3 cm), which was washed firstwith CH₂Cl₂ (100 mL) to remove p-anisaldehyde and then eluted withEt₂O-CH₂Cl₂ (1:1, 400 mL). After concentration under vacuum, alcoholS-23 was obtained as pale yellow oil, which was used for the next stepwithout further purification.

To a mixture of alcohol S-23 and triethylamine (1.79 mL, 12.9 mmol) inCH₂Cl₂ (13 mL) were added Ac₂O (0.609 mL, 6.45 mmol) and DMAP (47.2 mg,0.387 mmol) at room temperature and stirred for 2 h at room temperature.The reaction mixture was quenched with sat. NaHCO₃ aq. and the aqueousphase was extracted with CH₂Cl₂ three times. The combined organic phaseswere washed with brine, dried over Na₂SO₄, and concentrated undervacuum. Purification of the crude material by flash columnchromatography on silica gel (3% then 5% EtOAc in hexanes) affordedacetate S-24 (815 mg, 82% in 5 steps) as colorless syrup.

To a solution of THP-ether S-24 (1.03 g, 1.34 mmol) in Et₂O (134 mL) at0° C. were added thiophenol (freshly distilled, 0.687 mL, 6.70 mmol) andMgBr₂ ⁸ (4.93 g, 26.8 mmol) in one portion and the resultant whitesuspension was gradually warmed to room temperature over 50 min withvigorous stirring (reaction was carefully monitored by TLC to minimizeC38 primary TBS-ether deprotection). The reaction mixture was cooled to0° C., quenched with sat. NaHCO₃ aq., and vigorously stirred for 30 minat room temperature. The aqueous phase was extracted with EtOAc threetimes. Combined organic phases were washed with brine, dried over MgSO₄,and concentrated under vacuum. The crude residue was purified by flashcolumn chromatography on silica gel (5% for phenyl 2-tetrahydropyranylsulfide, 10% for starting material, then 20% EtOAc in hexanes fordesired product) to give alcohol S-16 (830 mg, 91%) as a colorless syrupalong with recovery of starting material S-24 (23.5 mg, 2% rsm).

S-16: [α]²⁰ _(D)−7.7 ,c, (0.12, CHCl₃). ¹H NMR (600 MHz, C₆D₆) δ: 5.04(1H, dd, J=8.6, 6.7 Hz, H-30), 5.02 (1H, s, C26=CHH), 4.84 (1H, d, J=1.2Hz, C26=CHH), 4.45 (1H, ddd, J=8.6, 5.9, 5.0 Hz, H-29), 4.19 (1H, dd,J=7.0, 5.4 Hz, H-27), 3.89 (1H, ddd, J=9.9, 9.6, 4.5 Hz, H-38a), 3.74(1H, ddd, J=9.9, 5.5, 4.5 Hz, H-38b), 3.68-3.57 (3H, m, H-20a, 20b, 33),3.51-3.45 (1H, m, H-23), 3.45-3.40 (2H, m, H-35, 36), 3.17 (1H, dd,J=4.6, 3.2 Hz, H-32), 2.33 (1H, ddd, J=14.4, 5.4, 5.0 Hz, H-28a), 2.20(qdd, J=7.3, 6.7, 4.6 Hz, H-31), 2.17 (1H, ddd, J=14.4, 7.0, 5.9 Hz,H-28b), 2.13-2.00 (4H, m, 20-OH, H-25, 34a, 37a), 1.79-1.68 (2H, m,H-21a, 37b), 1.67 (3H, s, COCH₃), 1.66-1.60 (1H, m, H-21b), 1.60-1.53(1H, m, H-22a), 1.50-1.42 (2H, m, H-22b, 34b), 1.37 (1H, ddd, J=12.6,4.1, 2.1 Hz, H-24a), 1.22 (3H, d, J=7.3 Hz, C31-CH₃), 1.10-1.04 (1H, m,H-24b), 1.01 (18H, s, 2× SiC(CH₃)₃), 0.96 (3H, d, J=6.4 Hz, C25-CH₃),0.11 (3H, s, SiCH₃), 0.11 (3H, s, SiCH₃), 0.10 (3H, s, SiCH₃), 0.04 (3H,s, SiCH₃). ¹³C NMR (125 MHz, C₆D₆) δ: 170.4, 151.9, 104.0, 78.7, 77.5,75.1, 75.0, 74.8, 70.7, 67.3, 64.7, 62.6, 59.7, 43.2, 39.2, 36.3, 35.6,35.5, 34.0, 32.6, 29.5, 26.1 (6C), 20.7, 18.5, 18.4, 18.1, 16.6, −4.1,−4.9, −5.2, −5.4. IR (film): 3446, 1742 cm⁻¹. HRMS (ESI) m/z: [M+H]⁺calcd for C₃₆H₆₉O₈Si₂, 685.4525; found, 685.4505.

Route 1, Compound 7:

To a solution of oxalyl chloride (74.2 μL, 0.876 mmol) in CH₂Cl₂ (4.0mL) at −78° C. was dropped dimethylsulfoxide (124 μL, 1.75 mmol)solution in CH₂Cl₂ (0.3 mL) over 5 min. The reaction mixture was stirredfor 15 min at −78° C. A solution of alcohol S-16 (400 mg, 0.584) inCH₂Cl₂ (1.5 mL) was added to the reaction at −78° C. over 5 min. Thereaction mixture was stirred for 30 min at −78° C. and was addedtriethylamine (406 μL, 2.92 mmol) at −78° C. After stirring for 10 minat −78° C., the reaction mixture was quenched with sat. NH₄C1 aq. Theaqueous phase was extracted with CH₂Cl₂ three times and combined organicphases were dried over Na₂SO₄ and the solvent was removed in vacuo. Theresidue was purified by flash column chromatography on silica gel elutedwith 8% EtOAc in hexanes to give aldehyde 7 (374 mg, 94%) as a colorlessoil. The aldehyde 7 was used for the next step without furtherpurification.

7: ¹H NMR (600 MHz, C₆D₆) δ: 9.56 (1H, dd, J=1.5, 1.5 Hz, CHO), 4.99(1H, br s, C26-CHH), 4.96 (1H, dd, J=8.3, 7.5 Hz, H-30), 4.82 (1H, d,J=1.2 Hz, 26-CHH), 4.38 (1H, ddd, J=8.3, 5.6, 5.6 Hz, H-29), 4.08 (1H,dd, J=6.2, 6.2 Hz, H-27), 3.90 (1H, ddd, J=9.9, 9.6, 4.5 Hz, H-38a),3.75 (1H, ddd, J=9.9, 5.5, 4.2 Hz, H-38b), 3.59 (1H, ddd, J=4.5, 4.1,3.7 Hz, H-33), 3.49-3.42 (2H, m, H-35,36), 3.41-3.34 (1H, m, H-23), 3.18(1H, dd, J=4.8, 3.7 Hz, H-32), 2.33-2.24 (3H, m, H-21a,21b,28a), 2.21(1H, ddd, J=7.2, 7.2, 5.0 Hz, H-31), 2.15 (1H, ddd, J=14.4, 6.4, 5.6 Hz,H-28b), 2.09-2.00 (3H, m, H-25,34a,37a), 1.76-1.71 (1H, m, H-37b), 1.69(3H, s, COCH₃), 1.62-1.56 (2H, m, H-22a,2b), 1.48 (1H, ddd, J=14.4, 4.5,4.5 Hz, H-34b), 1.30 (1H, ddd, J=12.5, 4.2, 2.1 Hz, H-24a), 1.21 (3H, d,J=7.3 Hz, C31-CH₃), 1.02 (9H, s, SiC(CH₃)₃), 1.01 (9H, s, SiC(CH₃)₃),0.93 (3H, d, J=6.4 Hz, C25-CH₃), 0.94-0.89 (1H, m, H-24b), 0.11 (3H, s,SiCH₃), 0.11 (6H, s, 2×SiCH₃), 0.04 (3H, s, SiCH₃).

Route 2, Compound S-19:

The ketal S-19 was prepared from previously reported compound S-25 (ee:>99%)²⁴ by the following 4 step sequences. 1) K₂CO₃, MeOH-THF (1:1), rt,16 h, 97%. 2) TBDPSCl, Et₃N, DMAP, CH₂Cl₂, rt, 36 h. 3) (COCl)₂, DMSO,CH₂Cl₂, -78° C. then Et₃N, −78° C. to rt, 30 min, 91% in 2 steps. 4)CSA, 2,2-dimethyl-1,3-propanediol, benzene, reflux, 12 h, 94%.

To TBDPS ether S-26 (2.37 g, 3.91 mmol) in THF (26 mL) were addedimidazole hydrochloride (122 mg, 1.17 mmol) and TBAF solution (1 M inTHF, 5.86 mL, 5.86 mmol) at room temperature and the reaction wasstirred for 1.5 h at room temperature. Solvent was removed toapproximately one third by volume and water was added to the mixture.The aqueous phase was extracted with EtOAc three times and the combinedorganic phases were dried over Na₂SO₄ and concentrated under reducedpressure. The crude residue was purified by flash column chromatographyon silica gel (3% then 20% EtOAc in hexanes containing 1% of Et₃N) togive alcohol S-27 (1.42 g, 98%) as a pale yellow oil.

To alcohol S-27 (1.42 g, 3.86 mmol) in CH₂Cl₂ (26 mL) were added Et₃N(2.15 mL, 15.4 mmol), acetic anhydride (0.729 mL, 7.72 mmol), and4-dimethylaminopyridine (47 mg, 0.386 mmol) at 0° C. The reaction wasstirred for 1 h at room temperature, added MeOH at 0° C., and furtherstirred for 5 min at room temperature. Sat. NaHCO₃ aq. was added to thereaction and the aqueous phase was extracted with CH₂Cl₂ three times.Combined organic phases were dried over Na₂SO₄ and evaporated. The crudeproduct was purified by flash column chromatography on silica gel (3%EtOAc in hexanes) to provide acetate S-19 (1.53 g, 97%) as a pale yellowoil.

S-19: [α]²⁰ _(D)−12.8 (c 1.03, CHCl₃). ¹H NMR (500 MHz, C₆D₆) δ: 5.90(1H, d, J=1.0 Hz, C═CHH), 5.56 (1H, d, J=1.5 Hz, C═CHH), 4.03 (2H, t,J=6.3 Hz, H-20a,b), 3.35-3.19 (4H, m, OCH₂CMe₂), 2.30-2.18 (1H, m,H-25), 1.97 (1H, dd, J=14.6, 5.4 Hz, H-24a), 1.83-1.62 (5H, m, 5 H),1.69 (3H, s, COCH₃), 1.09 (3H, d, J=6.8 Hz, C25-CH₃), 0.72 (s, 3H,CCH₃CH₃), 0.72 (3H, s, CCH₃CH₃). ¹³C NMR (125 MHz, C₆D₆) δ: 170.1,124.9, 123.7, 99.8, 70.2, 70.0, 64.6, 41.9, 40.5, 31.2, 29.4, 23.34,23.28, 22.8, 22.7, 20.5. IR (film): 1736 cm⁻¹. HRMS (ESI) m/z: [M+Na]⁺calcd for C₁₆H₂₇IO₄Na, 433.0846; found, 433.0866.

Route 2, Compound S-31:

To alcohol S-18²⁵ (452 mg, 0.723 mmol) in CH₂Cl₂ (7.2 mL) were addedethyl vinyl ether (0.207 mL, 2.17 mmol) and pyridiniump-toluenesulfonate(9.1 mg, 36.2 μmol) at room temperature. The reaction mixture wasstirred for 1.5 h at room temperature and then quenched with sat. NaHCO₃aq. The aqueous layer was extracted with CH₂Cl₂ three times and thecombined organic layers were dried over Na₂SO₄ and evaporated. Theobtained crude material S-28 was used for the next step without furtherpurification.

To a solution of MPM ether S-28 in CH₂Cl₂ (14 mL), t-BuOH (0.29 mL), andpH 7 phosphate buffer (1.4 mL) was added2,3-dichloro-5,6-dicyano-p-benzoquinone (328 mg, 1.45 mmol) in oneportion at room temperature and the resultant dark brown suspension wasvigorously stirred for 30 min at room temperature. The reaction mixturewas quenched with sat. NaHCO₃ aq. and further stirred for 10 min at roomtemperature. After partitioning into two layers, aqueous layer wasextracted twice with CH₂Cl₂. The combined organic phases were dried overNa₂SO₄ and concentrated under reduced pressure to give crude productS-29, which was used for the next step without further purification.

To alcohol S-29 in CH₂Cl₂ (7.2 mL) were added triethylamine (0.603 mL,4.34 mmol), acetic anhydride (0.273 mL, 2.89 mmol), and4-dimethylaminopyridine (8.8 mg, 0.072 mmol) at room temperature. Thereaction mixture was stirred at the same temperature for 12 h and wasquenched by adding sat. NaHCO₃ aq. The aqueous layer was extracted withCH₂Cl₂ three times and the combined organic layers were dried overNa₂SO₄ and concentrated in vacuo. The residue was purified by flashcolumn chromatography on silica gel (eluent: 1% then 5% EtOAc inhexanes) to give acetate S-30 (409 mg, 91% in 3 steps) as a pale yellowoil.

To a stirred solution of (1-ethoxy)ethyl ether S-30 (409 mg, 0.661 mmol)in Et₂O (22 mL) at 0° C. was added magnesium bromide (365 mg, 1.98 mmol)in one portion The resultant white suspension was gradually warmed toroom temperature over 35 min. The reaction mixture was cooled again to0° C. and was quenched with sat. NaHCO₃ aq. and stirred vigorously for30 min at room temperature. The aqueous layer was extracted with EtOActhree times and the combined organics were washed with brine, dried overNa₂SO₄, and concentrated under reduced pressure. The reside was purifiedby flash column chromatography on silica gel eluted with 10% EtOAc inhexanes to furnish alcohol S-31 (342 mg, 95%) as a colorless oil.

S-31: [α]²⁰ _(D)+2.8 (c 0.80, CHCl₃). ¹H NMR (500 MHz, C₆D₆) δ: 4.76(1H, dd, J=9.0, 8.1 Hz, H-30), 4.17 (1H, ddd, J=9.0, 6.8, 4.9 Hz, H-29),3.87 (1H, ddd, J=9.8, 9.8, 4.4 Hz, H-38a), 3.84-3.79 (1H, m, H-27a),3.79-3.72 (1H, m, H-27b), 3.70 (1H, ddd, J=9.8, 5.6, 4.2 Hz, H-38b),3.46-3.33 (3H, m, H-33,35,36), 3.09 (1H, dd, J=4.9, 3.4 Hz, H-32), 2.29(1H, br s, OH), 2.12 (dqd, J=8.1, 7.3, 4.9 Hz, H-31), 2.00 (dddd,J=14.1, 9.7, 4.2, 4.2 Hz, H-37a), 1.92 (1H, ddd, J=14.3, 4.2, 4.2 Hz,H-34a), 1.78-1.71 (2H, m, H-28a,28b), 1.70-1.64 (1H, m, H-37b), 1.63(3H, s, COCH₃), 1.38 (ddd, J=14.5, 4.5, 4.5 Hz, H, 34b), 1.09 (3H, d,J=7.3 Hz, C31-CH₃), 1.01 (9H, s, SiC(CH₃)₃), 1.00 (9H, s, SiC(CH₃)₃),0.10 (3H, s, SiCH₃), 0.09 (3H, s, SiCH₃), 0.09 (3H, s, SiCH₃), 0.03 (3H,s, SiCH₃). ¹³C NMR (125 MHz, C₆D₆) δ: 170.0, 78.8, 74.8, 74.5, 73.2,67.3, 65.0, 60.4, 59.7, 39.1, 35.6, 35.4, 34.4, 26.19 (3C), 26.16 (3C),20.5, 18.6, 18.5, 16.5, −4.0, −4.9, −5.1, −5.3. IR (film): 3474, 1741cm⁻¹. HRMS (ESI) m/z: [M+Na]⁺ calcd for C₂₇H₅₄O₇Si₂Na, 569.3300; found,569.3312.

Route 2, Compound S-32:

To alcohol S-31 (526 mg, 0.962 mmol) in CH₂Cl₂ (9.6 mL) were addedNaHCO₃ (808 mg, 9.62 mmol) and Dess-Martin periodinane (612 mg, 1.44mmol) at room temperature. The resultant suspension was stirred for 1 hat the same temperature. The reaction mixture was quenched with 10 wt %Na₂SO₃ aq and sat. NaHCO₃ aq and vigorously stirred for another 30 minat room temperature. The aqueous layer was extracted with CH₂Cl₂ threetimes. The combined organic layers were dried over Na₂SO₄ andconcentrated under vacuum. The residue was purified by flash columnchromatography on silica gel (eluent: 5% EtOAc in hexanes) to givealdehyde S-32 (475 mg, 91%) as a white amorphous.

S-32: [α]²⁰ _(D)−24.0 (c 1.02, CH₂Cl₂). ¹H NMR (600 MHz, C₆D₆) δ: 9.68(1H, dd, J=2.9, 2.3 Hz, CHO), 4.65 (1H, dd, J=9.4, 7.2 Hz, H-30), 4.58(1H, ddd, J=9.4, 6.5, 5.9 Hz, H-29), 3.85 (1H, ddd, J=9.7, 9.4, 4.1 Hz,H-38a), 3.68 (1H, ddd, J=9.7, 5.9, 4.1 Hz, H-38b), 3.44 (1H, ddd, J=4.1,3.5, 3.5 Hz, H-33), 3.40 (1H, ddd, J=9.4, 2.9, 1.8 Hz, H-36), 3.35 (1H,ddd, J=4.1, 3.8, 1.8 Hz, H-35), 3.10 (1H, dd, J=4.1, 3.5 Hz, H-32), 2.46(1H, ddd, J=15.8, 6.5, 2.3 Hz, H-28a), 2.35 (1H, ddd, J=15.8, 5.9, 2.9Hz, H-28b), 2.10 (1H, dqd, J=7.2, 7.0, 4.1 Hz, H-31), 1.99 (1H, dddd,J=14.1, 9.4, 4.1, 4.1 Hz, H-37a), 1.95 (1H, ddd, J=14.7, 3.8, 3.5 Hz,H-34a), 1.64 (1H, dddd, J=14.1, 9.4, 5.9, 2.9 Hz, H-37b), 1.61 (3H, s,COCH₃), 1.31 (1H, ddd, J=14.7, 4.3, 4.1 Hz, H-34b), 1.05 (3H, d, J=7.0Hz, C31-CH₃), 1.00 (9H, s, SiC(CH₃)₃), 0.96 (9H, s, SiC(CH₃)₃), 0.09(3H, s, SiCH₃), 0.08 (3H, s, SiCH₃), 0.04 (3H, s, SiCH₃), 0.00 (3H, s,SiCH₃). ¹³C NMR (125 MHz, C₆D₆) δ: 199.1, 169.9, 78.9, 75.5, 75.2, 68.3,67.2, 65.1, 59.6, 47.5, 39.5, 35.63, 35.62, 26.15 (3C), 26.12 (3C),20.4, 18.6, 18.5, 16.8, −4.0, −4.9, −5.1, −5.3. IR (film): 1741, 1734cm⁻¹. HRMS (ESI) m/z: [M+NH₄]⁺ calcd for C₂₇H₅₆NO₇Si₂, 562.3590; found,562.3565.

Route 2, Compound S-33:

To a mixture of CrCl₂ (10.7 mg, 87.2 μmol), (S)-sulfonamide ligand L(47.9 mg, 95.9 μmol), and proton sponge (20.5 mg, 95.9 μmol) in a glovebox was added MeCN (1.65 mL) and the resultant suspension was stirredfor 1 h at room temperature. In a separate flask, iodide S-19 (536 mg,1.31 mmol), aldehyde S-32 (475 mg, 0.872 mmol), NiCl₂.DEP (6.4 mg, 17.4μmol), LiCl (73.9 mg, 1.74 mmol), Mn (95.5 mg, 1.74 mmol), Cp₂ZrCl₂ (255mg, 0.872 mmol), 1,2-dimethoxyethane (0.55 mL) were mixed together andthe Cr-complex solution was transferred to the flask. AdditionalNiCl₂.DEP (6.4 mg each, 17.4 μmol) was added after 3 and 6 h and thereaction was further stirred for 1 h at room temperature. The reactionwas removed from the glove box and diluted with EtOAc. Florisil wasadded and the suspension was stirred vigorously for 30 min. Theresultant suspension was filtered through short pad of silica gel (1 cm,EtOAc) and concentrated. The crude material was purified by flashchromatography on silica gel (5% then 15% EtOAc in hexanes) to givealcohol S-33 (563 mg, 78%, dr: 50:1 based on integration ratio of ¹HNMR) as a colorless oil.

S-33: [α]²⁰ _(D)−10.1 (c 0.98, CH₂Cl₂). ¹H NMR (600 MHz, C₆D₆) δ: 5.44(1H, s, C26=CHH), 5.03 (1H, s, C26=CHH), 4.79 (1H, dd, J=8.8, 8.8 Hz,H-30), 4.56 (1H, dd, J=8.2, 2.9 Hz, H-27), 4.16 (1H, ddd, J=8.8, 8.5,3.5 Hz, H-29), 4.12-4.03 (2H, m, H-20a,20b), 3.86 (1H, ddd, J=10.5, 8.8,4.4 Hz, H-38a), 3.74 (1H, br s, OH), 3.70 (1H, ddd, J=10.5, 5.9, 4.1 Hz,H-38b), 3.46 (1H, ddd, J=4.7, 4.1, 3.5 Hz, H-33), 3.40 (1H, ddd, J=9.4,2.9, 1.8 Hz, H-36), 3.39-3.35 (2H, m, H-36, OCHHC(CH₃)₂), 3.34 (1H, d,J=11.7 Hz, OCHHC(CH₃)₂), 3.30 (1H, d, J=11.7 Hz, OCHHC(CH₃)₂), 3.28 (1H,d, J=11.7 Hz, OCHHC(CH₃)₂), 3.08 (1H, dd, J=5.3, 3.5 Hz, H-32), 2.69(dqd, J=7.0, 7.0, 4.7 Hz, H-25), 2.14 (1H, dqd, J=8.8, 7.0, 5.3 Hz,H-31), 2.05 (1H, dd, J=14.7, 4.7 Hz, H-24a), 2.03-1.91 (4H, m,H-28a,28b,34a,37a), 1.87 (1H, dd, J=14.7, 7.0 Hz, H-24b), 1.85-1.74 (4H,m, H-21a,21b,22a,22b), 1.73 (3H, s, COCH₃), 1.70 (3H, s, COCH₃), 1.66(1H, dddd, J=14.1, 8.8, 5.9, 2.9 Hz, H-37b), 1.46 (1H, ddd, J=14.7, 4.7,4.7 Hz, H-34b), 1.35 (3H, d, J=7.0 Hz, C25-CH₃), 1.09 (3H, d, J=7.0 Hz,C31-CH₃), 1.02 (9H, s, SiC(CH₃)₃), 1.00 (9H, s, SiC(CH₃)₃), 0.79 (3H, s,C(CH₃)₃), 0.75 (3H, s, C(CH₃)₃), 0.11 (3H, s, SiCH₃), 0.10 (3H, s,SiCH₃), 0.09 (3H, s, SiCH₃), 0.03 (3H, s, SiCH₃). ¹³C NMR (125 MHz,C₆D₆) δ: 170.2, 170.0, 159.2, 107.9, 100.4, 78.7, 75.3, 74.6 (2C), 74.4,70.1 (2C), 67.2, 64.9, 64.7, 59.7, 41.9, 38.7, 38.5, 35.6, 35.2, 31.0,30.9, 29.5, 26.22 (3C), 26.17 (3C), 23.4, 23.0, 22.8, 22.7, 20.6, 20.5,18.6, 18.5, 16.3, −3.9, −4.9, −5.1, −5.3. IR (film): 3500, 1740 cm⁻¹.HRMS (ESI) m/z: [M+Na]⁺ calcd for C₄₃H₈₀O₁₁Si₂Na, 851.5131; found,851.5145.

Route 2, Compound S-34:

To ketal S-33 (563 mg, 0.679 mmol) in CH₂Cl₂ (6.8 mL) were addedtriethylsilane (1.08 mL, 6.79 mmol) and TESOTf (0.460 mL, 2.04 mmol) at−78° C. and the reaction mixture was stirred for 1 h at the sametemperature. The reaction mixture was quenched with triethylamine (1 mL)and sat. NaHCO₃ aq. The aqueous layer was extracted with CH₂Cl₂ threetimes and the combined organic layers were dried over Na₂SO₄ andevaporated.

The crude material was co-evaporated with benzene, dissolved in CH₂Cl₂(6.8 mL), then 2,6-lutidine (0.632 mL, 5.43 mmol) and TBSOTf (0.934 mL,4.07 mmol) were added to the reaction mixture at 0° C. The reactionmixture was stirred for 1 h at room temperature and quenched with 0.5 MNaHSO₄ aq. The aqueous layer was extracted with CH₂Cl₂ and the combinedorganic layers were washed with brine, dried over Na₂SO₄, andconcentrated under reduced pressure. Purification of the crude by flashcolumn chromatography on silica gel eluted with 5% EtOAc in hexanesyielded TBS-ether S-34 (361 mg, 73% in 2 steps) as a pale yellow oil.

S-34: [α]²⁰ _(D)+5.7 (c 0.95, CHCl₃). ¹H NMR (500 MHz, C₆D₆) δ: 5.02(1H, br s, C26=CHH), 4.99 (1H, dd, J=7.3, 8.3 Hz, 1H), 4.84 (d, J=1.5Hz, C26=CHH), 4.40 (1H, ddd, J=8.4, 5.6, 5.6 Hz, H-29), 4.17-4.10 (3H,m, H-20a,20b,27), 3.90 (1H, ddd, J=9.9, 9.5, 4.4 Hz, H-38a), 3.74 (1H,ddd, J=9.9, 5.7, 4.4 Hz, H-38b), 3.59 (1H, ddd, J=4.9, 4.4, 4.4 Hz,H-33), 3.49-3.40 (3H, m, H-23,35,36), 3.18 (1H, dd, J=4.9, 3.4 Hz,H-32), 2.32 (1H, ddd, J=14.2, 5.6, 5.4 Hz, H-28a), 2.26-2.15 (2H, m,H-28b,31), 2.14-2.00 (3H, m, H-25,34a,37a), 1.88-1.77 (1H, m, H-21a),1.75-1.73 (3H, s, COCH₃), 1.71 (3H, s, COCH₃), 1.70-1.64 (2H, m,H-21b,37b), 1.54 (1H, dddd, J=9.8, 8.3, 4.9, 2.4 Hz, H-22a), 1.48 (1H,ddd, J=14.3, 4.6, 4.4 Hz, H-34b), 1.41-1.34 (2H, m, H-21b,24a), 1.21(3H, d, J=6.8 Hz, C31-CH₃), 1.07-1.03 (1H, m, H-24b), 1.02 (9H, s,SiC(CH₃)₃), 1.02 (9H, s, SiC(CH₃)₃), 0.96 (3H, d, J=6.8 Hz, C31-CH₃),0.11 (3H, s, 2×SiCH₃), 0.11 (3H, s, SiCH₃), 0.04 (3H, s, SiCH₃). ¹³C NMR(125 MHz, C₆D₆) δ: 170.1, 170.0, 152.0, 104.1, 78.8, 77.0, 75.3, 75.1,74.8, 71.1, 67.4, 64.9, 64.5, 59.8, 43.3, 39.3, 36.4, 35.59, 35.55,34.5, 32.5, 26.2 (6C), 25.4, 20.7, 20.6, 18.6, 18.5, 18.2, 16.7, −4.0,−4.8, −5.1, −5.3. IR (film): 1738 cm⁻¹. HRMS (ESI) m/z: [M+NH₄]⁺ calcdfor C₃₈H₇₄NO₉Si₂, 744.4897; found, 744.4892.

Route 2, Compound S-16:

To a solution of acetate S-34 (191 mg, 0.263 mmol) in acetone (5.3mL)/pH 7 phosphate buffer (0.53 mL) was added Amano lipase PS-800 (19mg) at room temperature. The resultant suspension was heated at 50° C.for four days. The reaction mixture was cooled to room temperature andfiltered through a pad of Celite. After removal of acetone, the residuewas added sat. NaHCO₃ aq and was extracted with EtOAc three times.Combined organic phases were dried over Na₂SO₄ and concentrated undervacuum. The crude product was purified by flash column chromatography onsilica gel eluted with 20% EtOAc in hexanes to give alcohol S-16 (175mg, 97%, colorless oil), which was identical with S-16 prepared fromS-17 via Route 1.

Compound 17:

To a mixture of CrCl₂ (21.4 mg, 0.174 mmol), (R)-sulfonamide ligand II(103 mg, 0.191 mmol), and proton sponge (40.9 mg, 0.191 mmol) in a glovebox was added MeCN (1.1 mL) and stirred for 1 h at room temperature. Ina separate flask, aldehyde 7 (297 mg, 0.435 mmol), bromide 6b (171 mg,0.261 mmol), NiCl₂.DEP (3.2 mg, 8.7 μmol), LiCl (73.8 mg, 1.74 mmol), Mn(95.5 mg, 1.74 mmol), Cp₂ZrCl₂ (152 mg, 0.522 mmol) were mixed togetherand the above Cr-complex solution was transferred to the flask.Additional NiCl₂.DEP (3.2 mg each, 8.7 μmol, four times) and bromide 6b(86 mg each, 0.13 mmol, twice) were added after 2, 3, 4, and 5 h and 2and 4 h, respectively. In total, the reaction mixture was stirred for 6h at room temperature. The reaction was removed from the glove box anddiluted with EtOAc (2.2 mL). Florisil was added and the suspension wasstirred vigorously for 30 min. The resultant suspension was filteredthrough a short pad of silica gel (1 cm, EtOAc) and concentrated. Thecrude material was purified by flash chromatography on silica gel (0%,10%, then 20% Et₂O in CH₂Cl₂) to give alcohol S-35 (499 mg, 91%,dr=20:1) as a white foam.

To a THF (8.0 mL) solution of allyl alcohol S-35 (499 mg, 0.395 mmol) ina flask covered with aluminum foil were added silver(I) oxide (229 mg,0.988 mmol) and silver trifluoromethanesulfonate (253 mg, 0.988 mmol) atroom temperature and the resultant black suspension was stirred for 12 hat room temperature. The reaction was quenched with triethylamine (0.5mL), diluted with EtOAc, and filtered through a pad of Celite (1.5 cm).After removal of the solvent, the residue was purified by flash columnchromatography on silica gel (20% then 30% EtOAc in hexanes) to givecyclized product 17 (378 mg, 78%) as a white foam. Note: transformationof S-35 to 17 is also achieved with use of other bases such as SrCO₃ andCaCO₃.

17: [α]²⁰ _(D)−40.4 (c 0.11, CHCl₃). ¹H NMR (600 MHz, C₆D₆) δ: 7.34 (2H,d, J=8.8 Hz, ArH), 6.69 (2H, d, J=8.8 Hz, ArH), 6.10 (1H, s, ArCH), 5.00(1H, br s, C19=CHH), 4.98 (1H, dd, J=7.9, 7.9 Hz, H-30), 4.96-4.95 (1H,m, C26=CHH), 4.95-4.93 (1H, m, C19=CHH), 4.83 (1H, d, J=1.2 Hz,C26=CHH), 4.57-4.54 (1H, m, H-20), 4.53 (1H, dd, J=3.5, 1.5 Hz, H-8),4.50 (1H, ddd, J=10.0, 9.7, 4.4 Hz, H-6), 4.38 (1H, dd, J=5.3, 1.2 Hz,H-11), 4.38-4.34 (1H, m, H-29), 4.15 (1H, dd, J=6.2, 6.2 Hz, H-27), 4.11(1H, s, H-13), 4.07-4.03 (1H, m, H-17), 4.04 (1H, dd, J=6.5, 5.3 Hz,H-10), 3.89 (ddd, J=9.5, 9.5, 4.4 Hz, H-38a), 3.76 (1H, ddd, J=6.5, 3.6,1.2 Hz, H-9), 3.76-3.71 (2H, m, H-3, 38b), 3.60-3.53 (2H, m, H-23, 33),3.47-3.41 (2H, m, H-35, 36), 3.35 (3H, s, CO₂CH₃), 3.23 (3H, s, ArOCH₃),3.15 (1H, dd, J=5.0, 3.5 Hz, H-32), 2.57 (1H, dd, J=15.8, 7.6 Hz, H-2a),2.53 (1H, dd, J=9.7, 1.5 Hz, H-7), 2.51-2.46 (1H, m, H-18a), 2.41-2.34(1H, m, H-15a), 2.30 (1H, ddd, J=14.3, 6.2, 5.0 Hz, H-28a), 2.27-2.08(7H, m, H-2b, 15b, 16a, 18b, 25, 28b, 31), 2.08-1.99 (3H, m, H-5a, 34a,37a), 1.94-1.80 (3H, m, H-16b, 21a, 22a), 1.79-1.72 (2H, m, H-21b, 37b),1.71 (3H, s, OCOCH₃), 1.66-1.58 (1H, m, H-22b), 1.51-1.43 (2H, m, H-24a,34b), 1.43-1.35 (1H, m, H-4a), 1.31-1.22 (2H, m, H-4b, 5b), 1.19 (3H, d,J=7.0 Hz, C31-CH₃), 1.13-1.05 (1H, m, H-24b), 1.01 (18H, s, 2 xSiC(CH₃)₃), 0.96 (3H, d, J=6.4 Hz, C25-CH₃), 0.11 (3H, s, SiCH₃), 0.10(3H, s, SiCH₃), 0.10 (3H, s, SiCH₃), 0.04 (3H, s, SiCH₃). ¹³C NMR (125MHz, C₆D₆) δ: 171.0, 170.0, 161.3, 152.8, 152.3, 128.8 (2C), 128.3,118.8, 114.1 (2C), 109.5, 109.0, 104.6, 103.9, 89.8, 83.6, 79.5, 78.8,78.7, 77.5, 77.1, 76.2, 75.2, 75.1, 74.8, 74.6, 74.2, 73.9, 71.4, 68.3,67.4, 64.8, 59.8, 54.8, 51.1, 43.4, 40.5, 39.1, 39.0, 36.4, 35.5, 35.4,34.6, 32.1, 31.7, 31.2, 30.6, 30.3, 29.3, 26.2 (3C), 26.1 (3C), 20.7,18.6, 18.5, 18.2, 16.6, −4.0, −4.8, −5.1, −5.3. HRMS (ESI) m/z: [M+Na]⁺calcd for C₆₅H₁₀₀O₁₈Si₂Na, 1247.6340; found, 1247.6308.

Compound S-35:

To a mixture of CrCl₂ (0.96 mg, 7.8 μmol), (R)-sulfonamide ligand II(4.7 mg, 8.6 μmol), and proton sponge (1.9 mg, 8.6 μmol) in a glove boxwas added MeCN (0.10 mL) and stirred for 1 h at room temperature. In aseparate flask, aldehyde 7 (26.7 mg, 39.1 μmol), iodide 6a (29.0 mg,41.0 μmol), NiCl₂.DEP (0.14 mg, 0.39 iimol, doped in LiCl), LiCl (6.6mg, 0.156 mmol), Mn (8.6 mg, 0.156 mmol), Cp₂ZrCl₂ (13.7 mg, 46.9 μmol)were mixed together and the above Cr-complex solution was transferred tothe flask. Additional NiCl₂.DEP (0.14 mg each, 0.39 μmol, twice, dopedin LiCl) and was added after 2 and 4 h, respectively. In total, thereaction mixture was stirred for 6 h at room temperature. The reactionmixture was removed from the glove box and diluted with EtOAc. Florisilwas added and the suspension was vigorously stirred for 30 min. Theresultant suspension was filtered through a short pad of silica gel (1cm, EtOAc) and concentrated in vacuo. The crude material was purified byflash chromatography on silica gel (0%, 10%, then 20% Et₂O in CH₂Cl₂) togive alcohol S-35 (44.4 mg, 90%, dr=18:1, white foam), which wasidentical with S-35 obtained by coupling of aldehyde 7 and bromide 6b.

Compound 18:

To a solution of ester 17 (93.3 mg, 76.1 μmol) in MeOH (2.3 mL) andwater (0.23 mL) at room temperature was added LiOH (91.3 mg, 3.80 mmol)and the reaction was stirred for 13 h at room temperature. The resultantsuspension was cooled to 0° C. and acidified with 0.5 M HCl aq. thenextracted with EtOAc four times. Combined organic phases were washedwith brine, dried over Na₂SO₄, and concentrated under vacuum to giveseco-acid S-36.

To a solution of 2-methyl-6-nitrobenzoic anhydride (MNBA, 157 mg, 0.457mmol) and 4,4-dimethylaminopyridine (111 mg, 0.913 mmol) in toluene (35mL) at 70° C. were dropped a solution of the seco-acid S-36 andN,N-diisopropylethylamine (79.5 μL, 0.457 mmol) in toluene (15 mL) over6 h by using syringe pump. After completion of the addition, thesolution was further stirred for 1 h at 70° C. The reaction mixture wascooled to 0° C. and then sat. NaHCO₃ aq was added and separated. Theaqueous phase was extracted with EtOAc three times and combined organicphases were dried over Na₂SO₄ and evaporated. The residue was purifiedby flash column chromatography on silica gel (10% EtOAc in hexanes) togive macrolactone 18 (67.8 mg, 77% in 2 steps) as a white foam. Note:macrolactonization of S-36 to 18 is also achieved with use of theYamaguchi protocol (seeYamaguchi et al., J. Am. Chem. Soc., 1992, 114,3162).

18: [α]²⁰ _(D)−43.5 (c 1.17, CHCl₃). ¹H NMR (600 MHz, C₆D₆) δ: 7.36 (2H,d, J=8.8 Hz, ArH), 6.73 (2H, d, J=8.8 Hz, ArH), 6.09 (1H, s, ArCH), 5.14(1H, br s, C19=CHH), 5.06 (1H, br s, C19=CHH), 4.97 (1H, br s, C26=CHH),4.86 (1H, dd, J=7.6, 5.9 Hz, H-30), 4.84-4.78 (1H, m, H-29), 4.81 (1H,br s, C26=CHH), 4.66 (1H, br d, J=10.0 Hz, H-20), 4.50 (1H, ddd, J=10.5,9.7, 4.2 Hz, H-6), 4.42 (1H, dd, J=3.1, 1.6 Hz, H-8), 4.38 (1H, dd,J=5.1, 1.3 Hz, H-11), 4.07 (1H, s, H-13), 4.05-3.93 (4H, m, H-3, 10, 17,38a), 3.86-3.79 (2H, m, H-27, 38b), 3.77-3.69 (2H, m, H-9, 23),3.56-3.46 (3H, m, H-33, 35, 36), 3.22 (3H, s, OCH₃), 3.19 (1H, dd,J=5.0, 3.5 Hz, H-32), 2.78 (1H, dd, J=16.7, 7.6 Hz, H-2a), 2.65 (1H,dddd, J=15.8, 7.6, 4.7, 2.6 Hz, H-18a), 2.52 (1H, dd, J=9.4, 1.5 Hz,H-7), 2.41-2.23 (6H, m, H-2b, 15a, 15b, 16a, 28a, 31), 2.20-2.05 (6H, m,H-18b, 21a, 25, 28b, 34a, 37a), 2.05-1.99 (1H, m, H-5a), 1.94 (1H, dddd,J=14.4, 11.4, 3.2, 2.7 Hz, H-22a), 1.89-1.82 (1H, m, H-22b), 1.79 (1H,dddd, J=14.1, 8.8, 5.3, 3.2 Hz, H-37b), 1.72 (1H, dddd, J=13.8, 10.3,5.3, 3.2 Hz, H-21b), 1.58-1.48 (3H, m, H-16b, 24a, 34b), 1.48-1.41 (1H,m, H-4a), 1.39-1.26 (2H, m, H-4b, 5b), 1.23 (3H, d, J=7.3 Hz, C31-CH₃),1.15-1.07 (1H, m, H-24b), 1.05 (3H, d, J=6.7 Hz, C25-CH₃), 1.04 (9H, s,SiC(CH₃)₃), 1.02 (9H, s, SiC(CH₃)₃), 0.15 (3H, s, SiCH₃), 0.14 (6H, s,2×SiCH₃), 0.09 (3H, s, SiCH₃). ¹³C NMR (100 MHz, C₆D₆) δ: 171.1, 161.4,152.9, 152.7, 128.7 (2C), 128.2, 119.0, 114.1 (2C), 109.3, 109.0, 104.8,103.8, 90.2, 83.8, 78.3, 78.2, 77.9, 76.0, 76.0, 75.7, 74.9, 74.8, 74.2,74.0, 73.8, 73.7, 70.1, 68.3, 67.2, 64.6, 59.9, 54.8, 44.0, 41.3, 39.6,39.3, 38.6, 36.4, 35.9, 35.7, 32.3, 31.0, 30.9, 30.2 (2C), 27.6, 26.3(3C), 26.2 (3C), 18.6, 18.5, 18.2, 16.7, −4.0, −4.7, −5.0, −5.2. HRMS(ESI) m/z: [M+H]⁺ calcd for H₆₂H₉₅O₁₆Si₂, 1151.6153; found, 1151.6197.

Compound 19:

To TBS-ether 18 (238 mg, 0.207 mmol) and imidazole (56.3 mg, 0.828 mmol)in MeCN (2.1 mL) was added HF-pyridine complex (70% HF content, 21.5 μL,0.828 mmol) at 0° C. and the reaction mixture was kept in a refrigerator(4° C.) for 6 h. The reaction mixture was quenched with sat. NaHCO₃ aq.at 0° C. and stirred for 10 min. The aqueous layer was extracted withEtOAc/hexanes (4:1) four times and the combined organic phases weredried over Na₂SO₄ and evaporated. The crude was purified by flash columnchromatography on silica gel (40% EtOAc in hexanes) to give alcohol 19(197 mg, 92%) as a colorless oil, contaminated with a small amount ofimidazole (ca. 5%), which was effectively removed at the next oxidationstep.

Compound 19:

To a solution of bis-TBS ether 18 (267 mg, 0.232 mmol) in THF (7.7 mL)was added TBAF solution (0.95 M in THF, buffered with 0.5 eq ofimidazole-hydrochloride, 0.98 mL, 0.928 mmol) at room temperature. Afterstirring for 34 h at room temperature, solvent was removed by a streamof nitrogen gas and redissolved in EtOAc and water. The aqueous layerwas extracted with EtOAc four times and the combined organic layer wasdried over Na₂SO₄. After removal of the solvent, the residue waspurified by flash column chromatography on silica gel (40% EtOAc inhexanes then EtOAc) to give diol S-37 (213 mg, 99%) as a whitesemisolid.

S-37: [α]²⁰ _(D)−104.8 (c 0.10, CHCl₃). ¹H NMR (600 MHz, C₆D₆) δ: 7.34(2H, d, J=8.8 Hz, 2×ArH), 6.71 (2H, d, J=8.8 Hz, 2×ArH), 6.06 (1H, s,ArCH), 5.31 (1H, br s, C19=CHH), 5.16 (1H, br s, C19=CHH), 4.75 (1H, brs, C26=CHH), 4.74 (1H, br s, C26=CHH), 4.70 (1H, br d, J=10.5 Hz, H-30),4.66-4.61 (2H, m, H-20, 29), 4.47 (1H, dd, J=3.5, 2.1 Hz, H-8), 4.36(1H, dd, J=5.1, 1.3 Hz, H-11), 4.37-4.31 (1H, m, H-6), 4.11 (1H, s,H-13), 4.07-4.01 (1H, m, H-17), 3.97 (1H, dd, J=6.5, 5.1 Hz, H-10),3.92-3.84 (4H, m, H-3, 27, 38a, 38b), 3.71-3.66 (1H, m, H-23), 3.63 (1H,ddd, J=6.5, 3.5, 1.3 Hz, H-9), 3.37-3.32 (1H, m, H-35), 3.29 (1H, br s,H-33), 3.24 (1H, br d, J=11.1 Hz, C35-OH), 3.22 (3H, s, OCH₃), 3.18-3.14(1H, m, H-36), 3.09 (1H, br s, C38-OH), 2.76 (1H, dd, J=17.2, 10.5 Hz,H-2a), 2.77-2.73 (1H, m, H-32), 2.67 (1H, dd, J=17.3, 2.3 Hz, H-2b),2.61 (1H, dddd, J=15.2, 7.6, 4.7, 2.6 Hz, H-18a), 2.57-2.51 (2H, m,H-15a, 31), 2.49 (1H, dd, J=9.4, 2.1 Hz, H-7), 2.38-2.30 (2H, m, H-16a,37a), 2.29-2.22 (2H, m, H-15b, 28a), 2.10-1.88 (6H, m, H-5a, 18b, 21a,22a, 28b, 34a), 1.81-1.73 (1H, m, H-25), 1.66 (1H, dddd, J=14.9, 4.7,4.5, 3.8 Hz, H-37b), 1.60-1.49 (3H, m, H-16b, 21b, 22b), 1.46 (1H, ddd,J=12.6, 4.4, 1.8 Hz, H-24a), 1.30-1.25 (1H, m, H-4a), 1.24-1.15 (3H, m,H-4b, 5b, 34b), 1.05-0.98 (1H, m, H-24b), 0.96 (3H, d, J=6.4 Hz,C25-CH₃), 0.87 (3H, d, J=7.9 Hz, C31-CH₃). ¹³C NMR (125 MHz, C₆D₆) δ:170.6, 161.3, 153.1, 152.4, 128.7, 128.6 (2C), 118.9, 114.1 (2C), 109.0,108.9, 105.0, 103.4, 90.4, 84.0, 80.6, 78.1, 77.5, 76.3, 75.8, 75.2,75.1, 74.7, 73.74, 73.72, 73.6, 73.32 73.1, 68.5, 66.7, 62.5, 60.7,54.7, 43.9, 40.8, 38.7, 36.2, 35.6, 35.2, 35.0, 34.7, 32.6, 31.6, 31.1,31.0, 30.5, 27.8, 17.9, 16.4. HRMS (ESI) m/z: [M+H]⁺ calcd forC₅₀H₆₇O₁₆, 945.4243; found, 945.4274.

To a stirred solution of diol S-37 (213 mg, 0.231 mmol, azeotropicallydried with benzene prior to use) in CH₂Cl₂ (7.7 mL) and triethylamine(0.77 mL) at −20° C. were added p-nitrobenzoyl chloride (128 mg, 0.693mmol) and 4,4-dimethylaminopyridine (8.5 mg, 69.3 μmol) and the reactionmixture was gradually warmed to 0° C. over 30 min. The reaction wasquenched with MeOH (0.2 mL) at 0° C. and the resultant mixture wasfurther stirred for 15 min at room temperature. The reaction was dilutedwith Et₂O (8 mL) to precipitate white solid and the reaction flask wassonicated for five seconds. After filtration through a Celite pad (1 cm)and evaporation of the solvent, the crude material was purified by flashcolumn chromatography on silica gel (30% then 40% EtOAc in hexanes) togive p-nitrobenzoate S-38 (242 mg, 98%) as a pale yellow amorphous. Theobtained product was co-evaporated with benzene before starting nextstep.

To a mixture of alcohol S-38 (242 mg, 0.226 mmol) and 2,6-lutidine (158μL, 1.35 mmol) in CH₂Cl₂ (7.5 mL) was dropped TBSOTf (0.155 mL, 0.678mmol) at −78° C. and the reaction mixture was stirred for 30 min at thesame temperature prior to the addition of sat. NaHCO₃ aq. The aqueousphase was extracted with CH₂Cl₂ twice and combined organic phases weredried over Na₂SO₄, concentrated under reduced pressure, and connected tohigh vacuum pump to remove remaining 2,6-lutidine. The obtained residuewas purified by flash column chromatography on silica gel (10% then 20%EtOAc in hexanes) to give TBS ether S-39 (259 mg, 97%) as a pale yellowamorphous.

To a solution of p-nitrobenzoate S-39 (39.8 mg, 33.6 μmol) in CH₂Cl₂(0.55 mL) and MeOH (1.1 mL) was added K₂CO₃ (4.6 mg, 34 μmol) at roomtemperature and the resultant suspension was stirred for 1.5 h at thesame temperature. The reaction was quenched with silica gel powder (0.3g), diluted with Et₂O (5 mL), and then passed through a pad of silicagel (0.5 cm), which was washed with Et₂O (60 mL). After removal of thesolvent, the crude residue was purified by preparative TLC (50%EtOAc inhexanes) to give alcohol 19 (33.0 mg, 95%) as a white semisolid.

19: [α]²⁰ _(D)−50.0 (c 0.45, CHCl₃). ¹H NMR (600 MHz, C₆D₆) δ: 7.36 (2H,d, J=8.8 Hz, 2×ArH), 6.73 (2H, d, J=8.8 Hz, 2×ArH), 6.09 (1H, s, ArCH),5.35 (1H, br s, C19=CHH), 5.16-5.12 (1H, m, C19=CHH), 4.94 (1H, br s,C26=CHH), 4.85 (1H, ddd, J=10.3, 7.3, 2.9 Hz, H-29), 4.81 (1H, dd,J=7.3, 3.5 Hz, H-30), 4.79 (1H, br s, C26=CHH), 4.68 (1H, d, J=9.4 Hz,H-20), 4.51 (1H, ddd, J=10.8, 9.7, 4.4 Hz, H-6), 4.41 (1H, dd, J=3.7,1.3 Hz, H-8), 4.37 (1H, dd, J=5.3, 1.2 Hz, H-11), 4.08 (1H, s, H-13),4.06-4.03 (1H, m, H-17), 4.02 (1H, dd, J=6.5, 5.3 Hz, H-10), 4.01-3.97(1H, m, H-3), 3.92-3.86 (1H, m, H-38a), 3.83 (1H, ddd, J=10.3, 8.5, 3.5Hz, H-38b), 3.78 (1H, d, J=11.4 Hz, H-27), 3.76-3.72 (1H, m, H-23), 3.71(1H, ddd, J=6.5, 3.7, 1.2 Hz, H-9), 3.48 (ddd, J=3.5, 3.5, 3.1 Hz,H-33), 3.33 (1H, ddd, J=4.0, 3.4, 2.1 Hz, H-35), 3.23 (3H, s, OCH₃),3.20 (1H, ddd, J=9.7, 3.4, 2.1 Hz, H-36), 3.03 (1H, dd, J=4.2, 3.1 Hz,H-32), 2.79 (1H, dd, J=16.8, 8.3 Hz, H-2a), 2.73 (1H, br s, C38-OH),2.66 (1H, dddd, J=15.5, 7.3, 4.7, 2.1 Hz, H-18a), 2.55 (1H, dd, J=9.7,1.3 Hz, H-7), 2.48 (1H, dd, J=16.8, 3.5 Hz, H-2b), 2.39-2.25 (4H, m,H-15a, 15b, 16a, 28a), 2.23-2.11 (4H, m, H-21a, 25, 31, 37a), 2.11-2.01(4H, m, H-5a, 18b, 28b, 34a), 2.00-1.95 (1H, m, H-22a), 1.91-1.85 (1H,m, H-22b), 1.84-1.78 (1H, m, H-21b), 1.61 (1H, ddd, J=12.3, 4.4, 2.1 Hz,H-24a), 1.53 (1H, dddd, J=13.5, 10.3, 6.4, 3.5 Hz, H-16b), 1.47 (1H,dddd, J=14.6, 6.2, 3.5, 3.2 Hz, H-37b), 1.43-1.33 (3H, m, H-4a, 4b,34b), 1.31-1.24 (1H, m, H-5b), 1.17-1.12 (1H, m, H-24b), 1.11 (3H, d,J=7.3 Hz, C31-CH₃), 1.05 (3H, d, J=6.4 Hz, C25-CH₃), 1.02 (9H, s,SiC(CH₃)₃), 0.13 (3H, s, SiCH₃), 0.10 (3H, s, SiCH₃). ¹³C NMR (125 MHz,C₆D₆) δ: 171.3, 161.4, 152.9, 152.2, 128.7 (2C), 128.6, 119.0, 114.1(2C), 109.4, 109.0, 105.4, 103.7, 90.3, 83.8, 79.2, 78.4, 77.4, 77.2,76.2, 75.8, 75.7, 75.1, 74.2, 74.1, 74.0, 73.8, 69.9, 68.3, 66.8, 64.0,61.2, 54.7, 44.3, 41.1, 39.3, 39.2, 39.1, 36.4, 35.9, 34.8, 32.4, 31.2,30.8, 30.3, 30.1, 27.5, 26.4 (3C), 18.7, 18.2, 16.4, −4.2, −4.6. HRMS(ESI) m/z: [M+H]⁺ calcd for C₅₆H₈₁O₁₆Si, 1037.5288; found, 1037.5239.

Compound S-40:

To a solution of alcohol 19 (33.0 mg, 31.8 μmol) in CH₂Cl₂ (1.1 mL) wereadded NaHCO₃ (26.7 mg, 0.318 mmol) and Dess-Martin periodinane (27.0 mg,63.6 μmol) at room temperature and the reaction mixture was stirred for1 h at the same temperature. The reaction was quenched by adding 10 wt %Na₂S₂O₃ aq. and sat. NaHCO₃ aq. and then vigoursly stirred for 30 min atroom temperature. The aqueous phase was extracted with CH₂Cl₂ threetimes and combined organic phases were dried over sodium sulfate. Afterevaporation of the solvent, the crude material was purified by flashchromatography on silica gel short plug (20% then 30% EtOAc in hexanes)to give aldehyde S-40 (31.8 mg, 96%) as a white semisolid.

S-40: ¹H NMR (600 MHz, C₆D₆) δ: 9.72 (1H, dd, J=1.6, 1.6 Hz, CHO), 7.36(2H, d, J=8.8 Hz, 2×ArH), 6.73 (2H, d, J=8.8 Hz, 2×ArH), 6.08 (1H, s,ArCH), 5.17 (1H, br s, C19=CHH), 5.10-5.06 (1H, m, C19=CHH), 4.93 (1H,br s, C26=CHH), 4.82-4.79 (1H, m, C26=CHH), 4.78 (1H, dd, J=7.0, 5.3 Hz,H-30), 4.75 (1H, ddd, J=7.5, 7.0, 2.6 Hz, H-29), 4.66 (1H, d, J=10.5 Hz,H-20), 4.49 (1H, ddd, J=10.5, 9.5, 4.4 Hz, H-6), 4.42 (1H, dd, J=3.4,1.6 Hz, H-8), 4.38 (1H, dd, J=5.3, 1.4 Hz, H-11), 4.07 (1H, s, H-13),4.04-4.01 (1H, m, H-17), 4.01 (1H, dd, J=6.4, 5.3 Hz, H-10), 3.97-3.91(1H, m, H-3), 3.77 (1H, d, J=11.1 Hz, H-27), 3.74-3.71 (1H, m, H-23),3.71 (1H, ddd, J=6.4, 3.4, 1.3 Hz, H-9), 3.52 (1H, ddd, J=7.1, 4.9, 2.3Hz, H-36), 3.44 (1H, ddd, J=5.0, 4.0, 3.5 Hz, H-33), 3.42 (1H, ddd,J=4.5, 4.0, 2.3 Hz, H-35), 3.22 (3H, s, OCH₃), 3.03 (1H, dd, J=4.7, 3.5Hz, H-32), 2.77 (1H, dd, J=16.7, 7.9 Hz, H-2a), 2.68-2.60 (2H, m, H-18a,37a), 2.52 (1H, dd, J=9.5, 1.6 Hz, H-7), 2.39-2.23 (7H, m, H-2b, 15a,15b, 16a, 28a, 31, 37b), 2.17 (1H, dddd, J=13.8, 11.4, 3.4, 2.8 Hz,H-21a), 2.12-1.99 (5H, m, H-5a, 18b, 25, 28b, 34a), 1.95 (1H, dddd,J=14.4, 11.4, 3.2, 2.8 Hz, H-22a), 1.83 (1H, dddd, J=14.4, 8.8, 5.3, 3.4Hz, H-22b), 1.73 (1H, dddd, J=13.8, 10.5, 5.3, 3.2 Hz, H-21b), 1.58-1.47(2H, m, H-16b, 24a), 1.47-1.40 (2H, m, H-4a, 34b), 1.36-1.23 (2H, m,H-4b, 5b), 1.16 (3H, d, J=7.3 Hz, C31-CH₃), 1.12-1.05 (1H, m, H-24b),1.03 (3H, d, J =6.4 Hz, C25-CH₃), 0.97 (9H, s, SiC(CH₃)₃), 0.08 (3H, s,SiCH₃), 0.04 (3H, s, SiCH₃). HRMS (ESI) m/z: [M+H]⁺ calcd forC₅₆H₇₉O₁₆Si, 1035.5132; found, 1035.5097.

Compound 20:

To a mixture of CrCl₂ (95.3 mg, 0.775 mmol), (S)-sulfonamide ligand I(266 mg, 0.853 mmol), and proton sponge (182 mg, 0.853 mmol) in a glovebox was added MeCN (7.8 mL) and stirred for 1 h at room temperature. Ina separate flask, aldehyde S-40 (160 mg, 155 iimol), iodoolefin 5²⁶ (214mg, 202 μmol), NiCl₂.DEP (0.28 mg, 0.78 wnol, doped in LiCl), LiCl (26.3mg, 0.620 mmol), were mixed together and the Cr-complex solution wastransferred to the flask. Additional NiCl₂.DEP (0.28 mg each, 0.78 wnol,doped in LiCl) was added after 15, 30, and 45 min and the reaction wasfurther stirred for 30 min at room temperature. The reaction mixture wasremoved from the glove box and diluted with EtOAc (8 mL) and potassiumserinate²⁷ (1 M aq., 8 mL) and the mixture was vigorously stirred for 30min. The resultant mixture was extracted with EtOAc/hexanes (1:1) threetimes, dried over sodium sulfate, and concentrated. The crude materialwas purified by flash column chromatography on silica gel (15% then 25%EtOAc in hexanes) to give allyl alcohol.

To a solution of the above allyl alcohol in CH₂Cl₂ (7.8 mL) were addedNaHCO₃ (130 mg, 1.55 mmol) and Dess-Martin periodinane (197 mg, 465μmol) at room temperature and the reaction mixture was stirred for 1.5 hat room temperature. Additional Dess-Martin periodinane (197 mg, 465μmol) and NaHCO₃ (130 mg, 1.55 mmol) was added to the reaction, whichwas stirred for further 1.5 h. The reaction was quenched with 10 wt. %Na₂S₂O₃ aq. and sat. NaHCO₃ aq. and vigorously stirred for 30 min. Theaqueous phase was extracted with CH₂Cl₂ three times and the combinedorganic phases were dried over Na₂SO₄ and concentrated under vacuum. Theresidue was purified by flash column chromatography on silica gel (30%EtOAc in hexanes) to give enone 20 (259 mg, 85% in 2 steps) as acolorless oil.

20: [α]²⁰ _(D)−41.5 (c 0.17, CHCl₃). ¹H NMR (600 MHz, C₆D₆) δ: 7.35 (2H,d, J=8.8 Hz, 2×CHArH), 7.25 (2H, d, J=8.5 Hz, 2×CH₂ArH), 6.85 (2H, d,J=8.5 Hz, 2×CH₂ArH), 6.79 (1H, dd, J=16.1, 6.7 Hz, H-40), 6.73 (2H, d,J=8.8 Hz, 2×CHArH), 6.40 (1H, dd, J=16.1, 0.9 Hz, H-39), 6.07 (1H, s,ArCH), 5.19 (1H, br s, C19=CHH), 5.10-5.04 (1H, m, C19=CHH), 4.95 (1H,br s, C26=CHH), 4.80 (1H, br s, C26=CHH), 4.84-4.77 (2H, m, H-29, 30),4.67 (1H, br d, J=10.3 Hz, H-20), 4.48 (1H, d, J=11.4 Hz, ArCHH),4.52-4.45 (1H, m, H-6), 4.41 (1H, dd, J=3.8, 1.5 Hz, H-8), 4.36 (1H, dd,J=5.3, 1.2 Hz, H-11), 4.30-4.24 (1H, m, H-53), 4.19 (1H, d, J=11.4 Hz,ArCHH), 4.06 (1H, s, H-13), 4.05-3.97 (4H, m, H-10, 17, 36, 51),3.96-3.89 (3H, m, H-3, 35, 48), 3.81 (1H, dd, J=10.3, 3.5 Hz, H-54a),3.80 (1H, br d, J=11.7 Hz, H-27), 3.83-3.75 (1H, m, H-50), 3.72 (1H,ddd, J=6.7, 3.8, 1.2 Hz, H-9), 3.69 (1H, dd, J=10.3, 6.2 Hz, H-54b),3.74-3.67 (1H, m, H-23), 3.65 (1H, ddd, J=6.7, 6.0, 0.9 Hz, H-41), 3.48(1H, ddd, J=4.4, 4.4, 3.4 Hz, H-33), 3.35 (3H, s, CH₂ArOCH₃), 3.23 (3H,s, CHArOCH₃), 3.17 (1H, dd, J=4.5, 3.4 Hz, H-32), 3.16 (1H, dd, J=17.9,7.3 Hz, H-37a), 3.10 (1H, dd, J=8.5, 3.8 Hz, H-47), 3.03 (1H, dd,J=17.9, 5.6 Hz, H-37b), 3.02 (1H, dd, J=16.5, 2.5 Hz, H-45a), 2.78 (1H,dd, J=16.8, 7.8 Hz, H-2a), 2.75-2.65 (2H, m, H-18a, 46), 2.61 (1H, dd,J=17.0, 4.1 Hz, H-43a), 2.53 (1H, dd, J=9.4, 1.5 Hz, H-7), 2.57-2.50(1H, m, H-42), 2.39 (1H, dd, J=16.8, 4.2 Hz, H-2b), 2.36-2.24 (7H, m,H-15a, 15b, 16a, 28a, 31, 43b, 45b), 2.24-2.18 (1H, m, H-21a), 2.15-2.07(4H, m, H-18b, 25, 28b, 34a), 2.04-1.96 (2H, m, H-5a, 52a), 1.96-1.88(2H, m, H-22a, 49a), 1.84-1.69 (3H, m, H-21b, 22b, 52b), 1.63-1.56 (2H,m, H-34b, 49b), 1.56-1.51 (1H, m, H-16b), 1.51-1.44 (2H, m, H-4a, 24a),1.36-1.24 (2H, m, H-4b, 5b), 1.21 (3H, d, J=7.3 Hz, C31-CH₃), 1.15-1.11(1H, m, H-24b), 1.09 (9H, s, SiC(CH₃)₃), 1.07 (9H, s, SiC(CH₃)₃), 1.04(3H, d, J=7.9 Hz, C25-CH₃), 1.02 (9H, s, SiC(CH₃)₃), 1.02 (9H, s,SiC(CH₃)₃), 0.98 (3H, d, J=6.7 Hz, C46-CH₃), 0.97 (9H, s, SiC(CH₃)₃),0.97 (3H, d, J=6.7 Hz, C42-CH₃), 0.29 (3H, s, SiCH₃), 0.28 (3H, s,SiCH₃), 0.27 (3H, s, SiCH₃), 0.26 (3H, s, SiCH₃), 0.16 (3H, s, SiCH₃),0.14 (3H, s, SiCH₃), 0.14 (3H, s, SiCH₃), 0.11 (3H, s, SiCH₃), 0.03 (3H,s, SiCH₃), 0.02 (3H, s, SiCH₃). ¹³C NMR (125 MHz, C₆D₆) δ: 207.9, 197.1,171.0, 161.4, 159.8, 152.9 (2C), 144.9, 132.5, 130.6, 129.7 (2C), 128.8(2C), 128.6, 119.0, 114.1 (2C), 114.0 (2C), 109.3, 109.0, 105.0, 103.8,90.2, 87.3, 83.8, 82.1, 81.2, 78.3, 78.1, 77.7, 76.1, 76.0, 75.7, 75.1,74.7, 74.2, 73.9, 73.8, 73.6, 72.9, 72.0, 71.3, 70.9, 70.4, 68.4, 68.0,66.1, 64.4, 54.7 (2C), 47.7, 45.9, 44.0, 42.6, 41.3, 39.4, 39.3, 39.0,38.7, 38.4, 36.3, 35.3, 33.7, 32.3, 31.2, 30.9, 30.3, 30.2, 28.8, 27.7,26.37 (3C), 26.32 (3C), 26.28 (3C), 26.26 (3C), 26.0 (3C), 18.6, 18.6,18.5, 18.4, 18.2, 18.1, 17.1, 16.7, 16.6, −3.6, −3.8, −3.9, −4.0, −4.2,−4.3, −4.6, −5.0, −5.1, −5.2. HRMS (ESI) m/z: [M+NH₄]⁺ calcd forC₁₀₆H₁₇₆NO₂₄Si₅, 1987.1423; found, 1987.1422.

Halichondrin A:

To a solution of enone 20 (20.6 mg, 10.4 μmol) in DMF (1.0 mL) and MeOAc(0.10 mL) was added TBAF solution (55 μL, 0.52 μmol, Aldrich, 0.95 M inTHF bufferized with 0.5 equiv. of imidazole hydrochloride) and TBAFsolution (55 μL, 0.52 μmol, TCI, product number T1125, 0.95 M in THFbufferized with 0.5 equiv. of imidazole hydrochloride) at roomtemperature. After stirring for 20 h at the same temperature, thesolvent was evaporated by stream of nitrogen gas. The residue was passedthrough silica gel pad twice (2 cm, eluent: 5% MeOH in EtOAc) to removeTBAF residue. After removal of the solvent, the crude product S-41 wasused for the next step without further purification.

The MPM ether S-41 was dissolved in CH₂Cl₂ (2.0 mL), t-BuOH (40 μL), andpH 7.0 phosphate buffer (0.20 mL), and DDQ (23.6 mg, 104 μmol) wereadded to the solution at room temperature. The reaction mixture wasvigorously stirred for 30 min at room temperature then quenched withsat. NaHCO₃ aq. and further stirred for 5 min. The aqueous layer wasextracted with CH₂Cl₂ six times and the combined organic layers weredried over Na₂SO₄ and concentrated under vacuum. The residue was passedthrough silica gel and washed with CH₂Cl₂ to remove p-anisaldehyde thenwith EtOAc, 5% MeOH in EtOAc. After removal of the solvent,co-evaporated with benzene, and dried under high vacuum, the crudeproduct S-42 was used for the next step without further purification.

The hemiacetal S-42 was dissolved in i-PrOH (2.0 mL, freshly distilledfrom sodium twice) and pyridinium p-toluenesulfonate (26.1 mg, 104 μmol)was added to the solution at room temperature. After stirring for 3 h atroom temperature, the reaction mixture was quenched with triethylamine(50 μL), diluted with EtOAc, and passed through plug of silica gel(bottom, 1 cm)/amino silica gel (top, 1 cm), which was washed with 20%MeOH in EtOAc. The obtained solution was concentrated under reducedpressure, and the residue was passed through silica gel eluted withCH₂Cl₂ to remove p-anisaldehyde then with 20% MeOH in EtOAc. Afterremoval of the solvent, the crude ¹H NMR shows the diastereomeric ratioat C38 position is 1:1.3 (21:22). The obtained crude mixture of 21 and22 was co-evaporated with benzene and further dried under high vacuum.

To a solution of acetal in CH₂Cl₂ (5.0 mL) was dropped TMSOTf (100 pt)at −78° C. and the reaction mixture was stirred for 10 min at the sametemperature. The reaction mixture was quickly poured into a solution ofsat. NaHCO₃ aq. (25 mL) in a separate flask at 0° C. with vigorousstirring (rare earth extra power stir bar and Yazawa magnetic stirrer,model KF-82 were used). The resultant solution was stirred for 1 h at 0°C. The aqueous layer was extracted with CH₂Cl₂ six times and thecombined organic layers were dried over Na₂SO₄ and concentrated undervacuum. The crude ¹H NMR shows the diastereomeric ratio at C38 positionis >10:1 (21:22). The crude material was purified by preparative TLC(0.5 mm thickness, 10×20 cm, EtOAc/CH₂Cl₂/MeOH=5:5:1, developed threetimes) to furnish halichondrin A (4.6 mg, 39% in 4 steps) as a whiteamorphous.

21: [α]²⁰ _(D)−69.2 (c 0.41, MeOH). ¹H NMR (600 MHz, ¹²CD₃OD) δ: 5.08(1H, d, J=1.8 Hz, C19=CHH), 5.03 (1H, d, J=1.8 Hz, C19=CHH), 4.88 (1H,br s, C26=CHH), 4.81 (1H, d, J=1.2 Hz, C26=CHH), 4.62 (1H, dd, J=7.3,4.4 Hz, H-30), 4.45 (1H, d, J=11.2 Hz, H-20), 4.37 (1H, dd, J=4.7, 2.9Hz, H-8), 4.32 (1H, ddd, J=10.0, 10.0, 4.1 Hz, H-6), 4.32-4.28 (2H, m,H-9,11), 4.25 (1H, ddd, J=11.2, 4.4, 2.1 Hz, H-29), 4.20 (1H, dd, J=3.2,2.1 Hz, H-10), 4.14-4.07 (4H, m, H-17,35,36,48), 4.05 (1H, ddd, J=2.3,2.3, 2.3 Hz, H-40), 3.99 (1H, ddd, J=9.5, 4.8, 4.1 Hz, H-50), 3.91-3.84(3H, m, H-3,33,53), 3.78 (1H, ddd, J=8.8, 4.8, 4.4 Hz, H-51), 3.75-3.70(1H, m, H-23), 3.69 (1H, dd, J=2.3, 2.3 Hz, H-41), 3.61 (1H, d, J=11.7Hz, H-27), 3.56 (1H, dd, J=2.3, 1.8 Hz, H-47), 3.53 (1H, s, H-13), 3.53(1H, dd, J=11.2, 4.7, Hz, H-54a), 3.47 (1H, dd, J=11.2, 6.5 Hz, H-54b),3.22 (1H, dd, J=6.5, 4.7 Hz, H-32), 2.94 (1H, dd, J=10.0, 2.3 Hz, H-7),2.82 (1H, dddd, J=15.8, 7.6, 4.7, 2.9 Hz, H-18a), 2.57 (1H, dd, J=17.9,9.7 Hz, H-2a), 2.45 (1H, dd, J=17.9, 1.8 Hz, H-2b), 2.40 (1H, dd,J=13.2, 6.2 Hz), 2.36-2.24 (6H, m), 2.20-2.13 (1H, m), 2.10-1.97 (4H,m), 1.92-1.79 (4H, m), 1.78-1.67 (4H, m), 1.60 (1H, ddd, J=14.2, 8.4,8.4 Hz, H-52b), 1.56-1.42 (4H, m), 1.42-1.28 (5H, m), 1.10 (3H, d, J=6.5Hz, C25-CH₃), 1.06 (3H, d, J=7.6 Hz, C31-CH₃), 1.02 (3H, d, J=7.0 Hz,C46-CH₃), 1.04-0.98 (1H, m, H-24b), 0.97 (3H, d, J=7.0 Hz, C42-CH₃). ¹³CNMR (125 MHz, ¹²CD₃OD) δ: 172.8, 153.3, 153.1, 114.8, 113.3, 112.9,105.7, 104.8, 98.4, 85.5, 82.3, 81.3, 81.2, 80.7, 79.0, 78.0 (2C), 77.6,77.4, 76.3, 76.0, 75.8, 75.5, 75.2, 75.1 (2C), 73.8, 73.7, 73.3, 73.1,73.0, 71.6, 69.6, 67.2, 65.6, 45.6, 45.0, 44.9, 41.1, 39.8, 37.93,37.90, 37.8, 37.51, 37.47, 37.2, 36.2, 33.0, 31.8, 31.34, 31.31, 30.85,30.82, 28.4, 27.11, 27.07, 18.4, 18.3, 18.1, 15.9. HRMS (ESI) m/z:[M+H]⁺ calcd for C₆₀H₈₇O₂₁, 1143.5734; found, 1143.5701.

TABLE 1 ¹H NMR chemical shifts of halichondrins (in CD₃OD) NaturalNatural Synthetic Natural Natural Hali B Hali C Hali A Nor A Homo A H22.44 2.44 2.45 2.44 2.44 H2 2.57 2.56 2.57 2.58 2.56 H3 3.88 3.88   3.87^(a) 3.89 3.88 H6 4.33 4.30   4.31 ^(a) 4.32 4.31 H7 2.98 2.98 2.93 2.932.93 H8 4.31 4.30 4.37 4.37 4.37 H9 4.13 4.10   4.31 ^(a) 4.31 4.31 H104.18 4.18 4.20 4.21 4.21 H11 4.60 4.40   4.31 ^(a) 4.31 4.31 H12 4.71 —— — — H13 1.98 2.27   3.53 ^(a) 3.53 3.53 H13 2.09 2.27 — — — H17 4.084.10   4.10 ^(a) 4.09 4.10 H18 2.32 2.32 2.34 2.32 2.32 H18 2.80 2.802.82 2.82 2.82 C19═CH₂ 5.02 5.02 5.03 5.02 5.02 C19═CH₂ 5.07 5.06 5.085.06 5.07 H20 4.46 4.43 4.45 4.44 4.44 H23 3.71 3.70 3.73 3.72 3.72C25—Me 1.10 1.09 1.10 1.09 1.09 C26═CH₂ 4.82 4.82 4.81 4.81 4.80 C26═CH₂4.88 4.87 4.88 4.86 4.85 H27 3.62 3.59 3.63 3.61 3.61 H29 4.25 4.25 4.254.24 4.24 H30 4.63 4.63 4.62 4.61 4.62 C31—Me 1.07 1.05 1.06 1.06 1.04H32 3.22 3.22 3.22 3.22 3.22 H33 3.87 3.88   3.87 ^(a) 3.87 3.88 H354.12 4.10   4.10 ^(a) 4.11 4.10 H36 4.10 4.10   4.10 ^(a) 4.09 4.10 H404.05 4.05 4.05 3.98 3.96 H41 3.69 3.68 3.70 3.69 3.66 C42—Me 0.94 0.960.97 0.97 0.94 C46—Me 1.01 1.00 1.02 0.96 0.93 H47 3.56 3.56 3.56 3.303.12 H48 4.10 4.10   4.10 ^(a) 3.77 3.58 H49 1.83 1.84 1.94 1.91 H492.27 2.28 2.09 2.16 H50 4.00 3.99 3.99 3.61 3.90 H51 3.78 3.78 3.78 3.784.02 H52 1.61 1.61 1.60 2.47 2.00 H52 1.75 1.75 1.75 2.47 2.00 H53 3.873.88   3.87 ^(a) — 4.23 H54 3.46 3.47 3.47 — 3.50 H54 3.53 3.53   3.53^(a) — — H55 — — — — 3.58 H55 — — — — 3.59 ^(a) overlap with otherprotons

TABLE 2 ¹³C NMR chemical shifts of halichondrins (in CD₃OD) NaturalNatural Synthetic Natural Natural Hali B Hali C Hali A Nor A Homo A C1172.8 172.8 172.8 172.8 172.8 C2 41.2 41.2 41.1 41.1 41.1 C3 74.9 74.775.1 75.1 75.1 C6 69.6 69.5 69.6 69.6 69.6 C7 79.1 79.0 79.0 79.0 79.0C8 75.8 76.1 75.8 75.8 75.9 C9 73.3 73.3 73.7 73.8 73.8 C10 78.0 73.085.5 85.5 85.5 C11 83.8 86.2 75.5 75.5 75.5 C12 82.5 114.2 113.3 113.4113.3 C13 49.4 49.3 82.3 82.4 82.3 C14 111.3 110.4 112.9 112.9 112.8 C1776.3 76.3 76.3 76.3 76.3 C18 39.7 39.7 39.8 39.8 39.8 C19 153.2 153.2153.1 153.2 153.0 C19═CH₂ 105.8 105.8 105.7 105.8 105.8 C20 76.1 76.376.0 76.0 75.9 C23 75.3 75.3 75.2 75.3 75.2 C25 37.5 37.5 37.2 37.2 37.2C25—Me 18.4 18.4 18.4 18.4 18.4 C26 153.2 153.2 153.3 153.2 153.2C26═CH₂ 104.8 104.8 104.8 104.8 104.8 C27 75.1 74.8 75.1 75.1 75.0 C2973.8 73.8 73.8 73.8 73.8 C30 77.3 77.3 77.4 77.3 77.3 C31 37.5 37.5 37.537.5 37.4 C31—Me 15.9 15.9 15.9 15.9 15.8 C32 78.0 78.0 78.0 77.9 77.9C33 65.5 65.5 65.6 65.6 65.6 C35 77.3 77.3 77.6 77.6 77.6 C36 78.0 78.078.0 78.0 78.0 C37 45.6 45.5 45.6 45.6 45.6 C38 114.8 114.9 114.8 114.9114.8 C39 45.0 45.0 45.0 44.9 44.9 C40 73.0 73.0 73.0 72.7 72.3 C41 80.880.8 80.7 80.7 81.0 C42 27.1 27.1 27.1 27.3 27.1 C42—Me 18.2 18.1 18.118.1 18.2 C44 98.4 98.4 98.4 98.5 98.1 C46 27.1 27.1 27.1 30.1 30.1C46—Me 18.3 18.3 18.3 17.5 17.6 C47 81.3 81.3 81.3 77.2 74.5 C48 75.174.8 73.3 68.2 65.2 C50 81.3 81.3 81.2 68.1 75.4 C51 73.1 73.2 73.1 79.178.4 C53 71.6 71.6 71.6 172.8 79.8 C54 67.1 67.1 67.2 — 75.0 C55 — — — —65.1Equilibration of halichondrin A (21) and C38-epi-halichondrin A (22):

To a solution of halichondrin A (21) or its C38-epimer (22) (ca. 0.05mg) in solvent (0.30 mL) was treated with acid (ca. 100 eq) at roomtemperature or at −78° C. The reaction was done at room temperature andmonitored by TLC until 21 and 22 were in equilibrium. For the reactionoperated at −78° C., the reaction mixture was stirred for 10 min at −78°C. then quenched with sat. NaHCO₃ aq. with vigorous stirring withoutdry-ice/acetone bath. The ratio of 21 and 22 were estimated by ¹H NMR(600 MHz, C₆D₆) and/or HPTLC (EtOAc/CH₂Cl₂/MeOH=5:5:1, R_(f)=0.28 for21, R_(f)=0.33 for 22).

Under the same conditions, equilibration of halichondrins B (1) and C(S-46), as well as norhalichondrin A methyl ester (S-43), was alsostudied, thereby showing their equilibration behavior to be identicalwith that of halichondrin A.

For illustration of the ratio estimation by NMR, ¹H NMR spectra ofhalichondrin A (21) and its C38-epimer (22), norhalichondrin methylester (S-43) and its C38-epimer (S-44), halichondrin B (1) and itsC38-epimer (S-45), and halichondrin C (S-46) and its C38-epimer (S-47)are shown in FIGS. 4 and 5. In all the series, the C19-proton resonanceswere found to be useful for estimating the ratio, cf., broken lines inred for the natural series vs. broken lines in blue for the C38-episeries.

C38-epi-Halichondrin A (22): ¹H NMR (600 MHz, CD₃OD): see NMR chart inTable 1. HRMS (ESI) m/z: [M+NH₄]⁺ calcd for C₆₀H₉₀NO₂₁, 1160.0000;found, 1160.6039.

Equilibration of norhalichondrin A methyl ester (S-43) andC38-epi-norhalichondrin A methyl ester (S-44):

Norhalichondrin A methyl ester (S-43): ¹H NMR (600 MHz, CD₃OD): see NMRchart in Table 1. HRMS (ESI) m/z: [M+Na]⁺ calcd for C₆₀H₈₄O₂₁Na,1163.5397; found, 1163.5366. C38-epi-Norhalichondrin A methyl ester(S-44): ¹H NMR (600 MHz, CD₃OD): see NMR chart in Table 1. HRMS (ESI)m/z: [M+Na]⁺ calcd for C₆₀H₈₄O₂₁Na, 1163.5397; found, 1163.5357.

Equilibration of halichondrin B (1) and C38-epi-halichondrin B (S-45):

Halichondrin B (1): see reference.¹⁶ C38-epi-Halichondrin B (S-45): ¹HNMR (600 MHz, CD₃OD): see NMR chart in Table 1. HRMS (ESI) m/z: [M+H]⁺calcd for C₆₀H₈₇O₁₉, 1111.5836; found, 1111.5805.

Equilibration of halichondrin C (S-46) and C38-epi-halichondrin C(S-47):

Halichondrin C (S-46): see reference.⁵ C38-epi-Halichondrin C (S-47): ¹HNMR (600 MHz, CD₃OD): see NMR chart in Table 1. HRMS (ESI) m/z: [M+Na]⁺calcd for C₆₀H₈₆O₂₀Na 1149.5605; found, 1149.5644.

Compound S-48:

To a mixture of CrCl₂ (18.1 mg, 0.147 mmol), (S)-sulfonamide ligand I(50.5 mg, 0.162 mmol), and proton sponge (34.6 mg, 0.162 mmol) in aglove box was added MeCN (1.5 mL) and stirred for 1 h at roomtemperature. In a separate flask, aldehyde S-40 (30.5 mg, 29.4 μmol),iodoolefin 23²⁸ (49.0 mg, 58.8 _(i)imol), NiCl₂.DEP (0.10 mg, 0.29 μmol,doped in LiCl), LiCl (5.0 mg, 0.12 mmol), were mixed together and theCr-complex solution was transferred to the flask. Additional NiCl₂.DEP(0.10 mg, 0.29 μmol) was added after 30 min and the reaction was furtherstirred for 30 min at room temperature. The reaction was removed fromthe glove box and diluted with EtOAc (1.5 mL) and potassium serinate (1M aq., 1.5 mL) and the mixture was stirred vigorously for 30 min. Theresultant mixture was extracted with EtOAc five times, dried over sodiumsulfate, and concentrated. The crude material was purified by flashcolumn chromatography on silica gel (20%, 30%, then 40% EtOAc inhexanes) to give allyl alcohol.

To a solution of the above allyl alcohol in CH₂Cl₂ (1.5 mL) were addedNaHCO₃ (24.7 mg, 0.294 mmol) and Dess-Martin periodinane (24.9 mg, 58.8μmol) at room temperature and the reaction mixture was stirred for 30min at room temperature. Additional Dess-Martin periodinane (12.5 mg,29.4 μmol) was added and the reaction was stirred for further 30 min.The reaction was quenched with 10 wt. % Na₂S₂O₃ aq. and sat. NaHCO₃ aq.and vigorously stirred for 30 min. The aqueous phase was extracted withCH₂Cl₂ three times and the combined organic phases were dried overNa₂SO₄ and concentrated under vacuum. The residue was purified bypreparative TLC (40% EtOAc in hexanes) to provide enone S-48 (43.7 mg,86% in 2 steps) as colorless oil.

S-48: M.p. 81-83° C. [α]²⁰ _(D)−54.1 (c 0.13, CHCl₃). ¹H NMR (600 MHz,C₆D₆) δ: 7.36 (2H, d, J=8.8 Hz, 2×CHArH), 7.27 (2H, d, J=8.5 Hz,2×CH₂ArH), 6.86 (2H, d, J=8.5 Hz, 2×CH₂ArH), 6.80 (1H, dd, J=16.1, 6.4Hz, H-40), 6.73 (2H, d, J=8.8 Hz, 2×CHArH), 6.41 (1H, dd, J=16.1, 1.0Hz, H-39), 6.08 (1H, s, ArCH), 5.20 (1H, br s, C19=CHH), 5.11-5.06 (1H,m, C19=CHH), 4.95 (1H, br s, C26=CHH), 4.80 (1H, br s, C26=CHH),4.85-4.78 (2H, m, H-29, 30), 4.68 (1H, br d, J=10.3 Hz, H-20), 4.53-4.47(1H, m, H-6), 4.48 (d, J=11.1 Hz, ArCHH), 4.42 (1H, dd, J=3.7, 1.5 Hz,H-8), 4.37 (1H, dd, J=5.3, 1.2 Hz, H-11), 4.21 (1H, d, J=11.1 Hz,ArCHH), 4.07 (1H, s, H-13), 4.06-3.93 (4H, m, H-3, 10, 17, 36),3.93-3.89 (1H, m, H-35), 3.81 (1H, br d, J=11.7 Hz, H-27), 3.78 (1H,ddd, J=8.5, 4.8, 2.1 Hz, H-51), 3.72 (1H, ddd, J=6.5, 3.7, 1.2 Hz, H-9),3.75-3.69 (1H, m, H-23), 3.67 (1H, ddd, J=6.4, 5.9, 1.0 Hz, H-41), 3.61(1H, ddd, J=4.2, 2.5, 1.8 Hz, H-48), 3.49 (2H, m, H-33, 50), 3.48 (3H,s, CO₂CH₃), 3.35 (3H, s, CH₂ArOCH₃), 3.23 (3H, s, CHArOCH₃), 3.16 (1H,dd, J=17.9, 7.3 Hz, H-37a), 3.17 (1H, dd, J=4.8, 3.4 Hz, H-32), 3.04(1H, dd, J=17.9, 5.3 Hz, H-37b), 2.93 (1H, dd, J=16.8, 3.4 Hz, H-45a),2.87 (1H, dd, J=16.1, 8.5 Hz, H-52a), 2.85 (1H, dd, J=8.8, 1.8 Hz,H-47), 2.78 (1H, dd, J=17.0, 7.8 Hz, H-2a), 2.74 (1H, ddddd, J=15.5,7.3, 2.6, 2.2, 2.2 Hz, H-18a), 2.66 (1H, ddqd, J=9.1, 8.8, 6.7, 3.4 Hz,H-46), 2.58-2.50 (3H, m, H-7, 42, 43a), 2.48 (1H, dd, J=16.1, 4.8 Hz,H-52b), 2.40 (1H, dd, J=17.0, 4.4 Hz, H-2b), 2.37-2.17 (8H, m, H-15a,15b, 16a, 21a, 28a, 31, 43b, 45b), 2.16-2.07 (4H, m, H-18b, 25, 28b,34a), 2.05-2.00 (1H, m, H-5a), 1.99-1.92 (1H, m, H-22a), 1.87 (1H, ddd,J=14.7, 2.6, 2.5 Hz, H-49a), 1.85-1.79 (1H, m, H-22b), 1.73 (1H, dddd,J=13.5, 10.3, 5.0, 3.2 Hz, H-21b), 1.61 (ddd, J=14.6, 4.7, 4.7 Hz,H-34b), 1.58-1.52 (1H, m, H-16b), 1.52-1.44 (3H, m, H-4a, 24a, 49b),1.37-1.27 (2H, m, H-4b, 5b), 1.22 (3H, d, J=7.3 Hz, C31-CH₃), 1.12-1.06(1H, m, H-24b), 1.04 (3H, d, J=6.2 Hz, C25-CH₃), 1.04 (9H, s,SiC(CH₃)₃), 1.03 (9H, s, SiC(CH₃)₃), 0.97 (9H, s, SiC(CH₃)₃), 0.93 (3H,d, J=6.7 Hz, C46-CH₃), 0.92 (3H, d, J=6.7 Hz, C42-CH₃), 0.16 (3H, s,SiCH₃), 0.13 (3H, s, SiCH₃), 0.12 (3H, s, SiCH₃), 0.07 (3H, s, SiCH₃),0.05 (3H, s, SiCH₃), −0.05 (3H, s, SiCH₃). ¹³C NMR (125 MHz, C₆D₆) δ:208.4, 197.1, 171.8, 171.1, 161.4, 159.8, 152.9 (2C), 144.9, 132.5,130.7, 129.7 (2C), 128.8 (2C), 128.7, 119.0, 114.1 (2C), 114.0 (2C),109.3, 109.0, 105.0, 103.8, 90.3, 84.6, 83.8, 82.1, 78.3, 78.2, 78.0,77.8, 76.1, 76.0, 75.7, 75.1, 74.7, 74.2, 74.0, 73.8, 73.7, 71.2, 70.3,68.4, 66.2, 65.9, 64.7, 64.5, 54.8, 54.7, 51.1, 46.7, 45.7, 44.0, 42.7,41.3, 39.4, 39.3, 38.9, 38.5, 37.1, 36.4, 35.4, 33.7, 32.3, 31.2, 30.9,30.3, 30.2, 29.9, 27.7, 36.5 (3C), 26.4 (3C), 26.3 (3C), 18.6, 18.5,18.4, 18.2, 16.9, 16.5, 16.4, −2.6, −3.6, −4.0, −4.5, −5.0, −5.1. HRMS(ESI) m/z: [M+Na]⁺ calcd for C₉₄H₁₄₂O₂₄Si₃Na, 1761.9091; found,1761.9086.

Norhalichondrin A:

To a solution of enone S-48 (18.4 mg, 10.5 μmol) in DMF (1.1 mL) andMeOAc (0.11 mL) was added TBAF solution (55 μL, 0.52 μmol, Aldrich, 0.95M in THF bufferized with 0.5 equiv. of imidazole hydrochloride) and TBAFsolution (55 μL, 0.52 μmol, TCI, product number T1125, 0.95 M in THFbufferized with 0.5 equiv. of imidazole hydrochloride) at roomtemperature. After stirring for 24 h at the same temperature, thesolvent was evaporated by stream of nitrogen gas. The residue was passedthrough silica gel pad twice (2 cm, eluent: 5% MeOH in EtOAc) to removeTBAF residue. After removal of the solvent, the crude product S-49 wasused for the next step without further purification.

The MPM ether S-49 was dissolved in CH₂Cl₂ (2.1 mL), t-BuOH (42 μL), andpH 7.0 phosphate buffer (0.21 mL), and DDQ (23.8 mg, 105 μmol) was addedto the solution at room temperature. The reaction mixture was vigorouslystirred for 30 min at room temperature then quenched with sat. NaHCO₃aq. and further stirred for 5 min. The aqueous layer was extracted withCH₂Cl₂ six times and the combined organic layers were dried over Na₂SO₄and concentrated under vacuum. The residue was passed through silica geland washed with CH₂Cl₂ to remove p-anisaldehyde then with EtOAc, 5% MeOHin EtOAc. After removal of the solvent, co-evaporated with benzene, anddried under high vacuum, the crude product S-50 was used for the nextstep without further purification.

The hemiacetal S-50 was dissolved in i-PrOH (2.1 mL, freshly distilledfrom sodium twice) and pyridinium p-toluenesulfonate (26 mg, 105 μmol)was added to the solution at room temperature. After stirring for 3 h atthe same temperature, the reaction mixture was quenched withtriethylamine (50 μL), diluted with EtOAc, and passed through plug ofsilica gel (bottom, 1 cm)/amino silica gel (top, 1 cm), which was washedwith 20% MeOH in EtOAc. The obtained solution was concentrated underreduced pressure, and the residue was passed through silica gel elutedwith CH₂Cl₂ to remove p-anisaldehyde then with 20% MeOH in EtOAc. Afterremoval of the solvent, the crude ¹H NMR shows the diastereomeric ratioat C38 position is 1:1 (S-43:S-44). The obtained crude mixture of S-43and S-44 was co-evaporated with benzene and further dried under highvacuum.

To a solution of above acetal in CH₂Cl₂ (5.0 mL) was dropped TMSOTf (100μL) at −78° C. and the reaction mixture was stirred for 10 min at thesame temperature. The reaction mixture was quickly poured into asolution of sat. NaHCO₃ aq. (25 mL) in a separate flask at 0° C. withvigorous stirring (rare earth extra power stir bar and Yazawa magneticstirrer, model KF-82 were used). The resultant solution was stirred for1 h at 0° C. The aqueous layer was extracted with CH₂Cl₂ six times andthe combined organic layers were dried over Na₂SO₄ and concentratedunder vacuum. The crude ¹H NMR shows the diastereomeric ratio at C38position is >10:1 (S-43:S-44). The crude material was purified bypreparative TLC (0.5 mm thickness, 10×20 cm, EtOAc/CH₂Cl₂/MeOH=5:5:1,developed three times) to furnish norhalichondrin A methyl ester S-43 asa white amorphous.

To methyl ester S-43 in THF (1.8 mL) was added LiOH solution (1 M aq.,0.30 mL) at room temperature and the reaction mixture was stirred for 2h at the same temperature. The reaction mixture was diluted with water(0.9 mL) and THF was removed by a stream of nitrogen gas. After coolingto 0° C., the reaction mixture was quenched with 1 M HCl aq (0.3 mL) andextracted with EtOAc five times. The combined organic phases were driedover Na₂SO₄ and concentrated under reduced pressure. The crude waspurified by preparative TLC (EtOAc/CH₂Cl₂/MeOH=5:5:1, developed threetimes) to give product, which was further purified by polystyrene column(TSK G3000S, loaded with 50% EtOH/H₂O) eluted with 0%, 25%, 50% EtOH/H₂Oto give norhalichondrin A (24, 3.5 mg, 30% in 5 steps) as a whiteamorphous.

24: ¹H NMR (600 MHz, ¹²CD₃OD) δ: 5.06 (1H, d, J=1.5 Hz, C19=CHH), 5.02(d, J=1.8 Hz, C19=CHH), 4.86 (1H, m, C26=CHH), 4.81 (1H, d, J=1.2 Hz,C26=CHH), 4.62 (1H, dd, J=7.3, 4.7 Hz, H-30), 4.44 (1H, d, J=11.1 Hz,H-20), 4.39-4.35 (1H, m, H-8), 4.35-4.29 (3H, m, H-6,9,11), 4.24 (1H,ddd, J=11.2, 4.3, 2.1 Hz, H-29), 4.20 (1H, dd, J=3.2, 2.3 Hz, H-10),4.16-4.05 (3H, m, H-17,35,36), 4.00-3.96 (1H, m, H-40), 3.92-3.85 (2H,m, H-3,33), 3.81-3.75 (2H, m, H-48,51), 3.74-3.67 (2H, m, H-23,41),3.65-3.59 (2H, m, H-27,50), 3.53 (1H, s, H-13), 3.33-3.28 (1H, m, H-47),3.21 (1H, dd, J=6.4, 4.7 Hz, H-32), 2.93 (1H, dd, J=9.8, 2.2 Hz, H-7),2.83 (1H, ddd, J=16.0, 8.1, 2.1 Hz, H-18a), 2.58 (1H, dd, J=17.6, 9.7Hz, H-2a), 2.48 (2H, d, J=6.7 Hz, H-52a,52b), 2.45 (1H, dd, J=17.6, 2.1Hz, H-2b), 2.39 (1H, dd, J=13.2, 6.2 Hz, H-37a), 2.37-2.23 (6H, m,H-18b), 2.20-2.12 (2H, m), 2.10-1.97 (6H, m), 1.94 (1H, ddd, J=14.9,3.1, 3.1 Hz, H-49b), 1.91-1.79 (2H, m), 1.76-1.66 (3H, m), 1.63-1.45(3H, m), 1.43-1.31 (5H, m), 1.10 (3H, d, J=6.4 Hz, C25-CH₃), 1.06 (3H,d, J=7.0 Hz, C31-CH₃), 1.04-1.00 (1H, m, H-24b), 0.98 (3H, d, J=6.4 Hz,C42-CH₃), 0.96 (3H, d, J=6.7 Hz, C46-CH₃). ¹³C NMR (125 MHz, ¹²CD₃OD) δ:172.8 (2C), 153.3, 153.1, 114.8, 113.3, 112.9, 105.7, 104.8, 98.5, 85.5,82.3, 80.6, 79.0, 77.9 (3C), 77.6, 77.36, 77.27, 76.3, 76.0, 75.8, 75.5,75.2, 75.0 (2C), 73.78, 73.74, 72.6, 69.6, 68.14, 68.11, 65.6, 45.5,44.9 (2C), 41.1, 39.8, 38.3, 38.1, 37.8, 37.5, 37.1, 35.8, 32.9, 31.8,31.32, 31.29, 30.8 (3C), 30.1, 28.4, 27.3, 18.4, 18.1,17.4, 15.8. HRMS(ESI) m/z: [M+NH₄]⁺ calcd for C₅₉H₈₆NO₂₁, 1144.5687; found, 1144.5646.

TABLE 3 NMR chemical shifts of natural and synthetic norhalichondrin A(24, in CD₃OD)²⁹ ¹H NMR (δ in ppm) ¹³C NMR (δ in ppm) Natural SyntheticNatural Synthetic H2 2.44 2.45 C1 172.8 172.8 H2 2.58 2.58 C2 41.1 41.1H3 3.89 3.88 C3 75.1 75.0 H6 4.32 4.32 C6 69.6 69.6 H7 2.93 2.93 C7 79.077.9 H8 4.37 4.37 C8 75.8 75.8 H9 4.31 4.31 C9 73.8 73.7 H10 4.21 4.20C10 85.5 85.5 H11 4.31 4.31 C11 75.5 75.5 H13 3.53 3.53 C12 113.4 113.3H17 4.09 4.10 C13 82.4 82.3 H18 2.32 2.33 C14 112.9 112.9 H18 2.82 2.83C17 76.3 76.3 C19═CH₂ 5.02 5.02 C18 39.8 39.8 C19═CH₂ 5.06 5.06 C19153.2 153.1 H20 4.44 4.44 C19═CH₂ 105.8 105.7 H23 3.72 3.72 C20 76.076.0 C25—Me 1.09 1.10 C23 75.3 75.2 C26═CH₂ 4.81 4.81 C25 37.2 37.1C26═CH₂ 4.86 4.86 C25—Me 18.4 18.4 H27 3.61 3.62 C26 153.2 153.2 H294.24 4.24 C26═CH₂ 104.8 104.8 H30 4.61 4.62 C27 75.1 75.0 C31—Me 1.061.06 C29 73.8 73.7 H32 3.22 3.21 C30 77.3 77.4 H33 3.87 3.88 C31 37.537.5 H35 4.11 4.10 C31—Me 15.9 15.8 H36 4.09 4.10 C32 77.9 77.9 H40 3.983.98 C33 65.6 65.6 H41 3.69 3.70 C35 77.6 77.6 C42—Me 0.97 0.98 C36 78.077.9 C46—Me 0.96 0.96 C37 45.6 45.5 H47 3.30 3.30 C38 114.9 114.8 H483.77 3.78 C39 44.9 44.9 H49 1.94 1.94 C40 72.7 72.6 H49 2.09 2.10 C4180.7 80.6 H50 3.61 3.62 C42 27.3 27.3 H51 3.78 3.78 C42—Me 18.1 18.1 H522.47 2.48 C44 98.5 98.5 H52 2.47 2.48 C46 30.1 30.1 C46—Me 17.5 17.4 C4777.2 77.2 C48 68.2 68.1 C50 68.1 68.1 C51 79.1 79.0 C53 172.8 172.8

REFERENCES AND NOTES

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Soc. 2009, 131, 16678 and references cited therein.-   3. Buszek, K. R.; Fang, F. G.; Forsyth, C. J.; Jung, S. H.; Kishi,    Y.; Scola, P. M.; Yoon, S. K. Tetrahedron Lett. 1992, 33, 1553.-   4. In the previous synthesis of halichondrins B and C, the C8-C14    polycycle was built after the macrolactonization.-   5. Yamamoto, A.; Ueda, A.; Bremond, P.; Tiseni, P. S.; Kishi, Y. J.    Am. Chem. Soc. 2012, 134, 893 and references cited therein.-   6. Anisylidene formation of β-10 gave a single stereoisomer, whose    stereochemistry was assigned, based on the NOE experiments done on    6a.-   7. For example, see: (a) Aicher, T. D.; Kishi, Y. Tetrahedron Lett.    1987, 28, 3463. (b) Usanov, D. L.; Yamamoto, H. J. Am. Chem. Soc.    2011, 133, 1286.-   8. For possibly relevant examples, see: (a) Mahadevan, A.;    Fuchs, P. L. J. Am. Chem. Soc. 1995, 117, 3272. (b) Knapp, S.;    Naughton, A. B. J.; Murali Dhar, T. G. Tetrahedron Lett. 1992, 33,    1025.-   9. Reich, H. J.; Peake, S. L. J. Am. Chem. Soc. 1978, 100, 4888.-   10. Kang, B.; Mowat, J.; Pinter, T.; Britton, R. Org. Lett. 2009,    11, 1717.-   11. Shiina, I.; Kubota, M.; Ibuka, R. Tetrahedron Lett. 2002, 43,    7535.-   12. For recent examples, see for example: (a) Phillips, S. T.;    Shair, M. D. J. Am. Chem. Soc. 2007, 129, 6589; Fortner, K. C.;    Kato, D.; Tanaka, Y.; Shair, M. D. J. Am. Chem. Soc. 2010,    132, 275. (b) Ravindar, K.; Reddy, M. S.; Lindqvist, L.; Pelletier,    J.; Deslongchamps, P. Org. Lett. 2010,12, 4420. (c) Tlais , S. F.;    Dudley, G. B. Org. Lett. 2010,12, 4698.-   13. TMSOTf was most effective to induce the equilibration. Other    Lewis acids, including TBSOTf and BF₃.Et₂O, were also found to be    effective.-   14. Solvent tested included: (a) no-oxygen containing solvents:    toluene and dichloroethane; (b) oxygen-containing solvents; THF and    H₂O.-   15. Fang, F. G.; Kishi, Y.; Matelich, M. C.; Scola, P. M.    Tetrahedron Lett. 1992, 33, 1557.-   16. Aicher, T. D.; Buszek, K. R.; Fang, F. G.; Forsyth, C. J.;    Jung, S. H.; Kishi, Y.; Matelich, M. C.; Scola, P. M.; Spero, D. M.;    Yoon, S. K. J. Am. Chem. Soc. 1992, 114, 3162.-   17. Freshly prepared according to the literature: (a) Murray, R. W.;    Singh, M. Org. Synth. 1997, 74, 91; 1998, Coll. Vol. 9, 288. (b)    Cerré, C.; Hofmann, A. F.; Schteingart, C. D. Tetrahedron, 1997, 53,    435.-   18. Liu, S.; Kim, J. T.; Dong, C.-G.; Kishi, Y. Org. Lett. 2009, 11,    4520.-   19. Standard TBAF-mediated TBDPS deprotection resulted in partial    elimination of chloride to give trans-enyne by-product.-   20. Hara, S.; Dojo, H.; Takinami, S.; Suzuki, A. Tetrahedron Lett.    1983, 24, 731.-   21. (a) Choi, H.; Demeke, D.; Kang, F.-A.; Kishi, Y.; Nakajima, K.;    Nowak, P.; Wan, Z.-K.; Xie, C. Pure Appl. Chem. 2003, 75,1. (b) Guo,    H.; Dong, C.-G.; Kim, D.-S.; Urabe, D.; Wang, J.; Kim, J. T.; Liu,    X.; Sasaki, T.; Kishi, Y. J. Am. Chem. Soc. 2009, 131, 15387.-   22. Dong, C.-G.; Henderson, J. A.; Kaburagi, Y.; Sasaki, T.; Kim,    D.-S.; Kim, J. T.; Urabe, D.; Guo, H.; Kishi, Y. J. Am. Chem. Soc.    2009, 131, 15642.-   23. Kim, S.; Park, J. H. Tetrahedron Lett. 1987, 28, 439.-   24. Shan, M.; Kishi, Y. Org. Lett. 2012, 14, 660.-   25. (a) Chen, C.-L.; Namba, K.; Kishi, Y. Org. Lett. 2009,    11, 409. (b) Aicher, T. D.; Buszek, K. R.; Fang, F. G.; Forsyth, C.    J.; Jung, S. H.; Kishi, Y.; Scola, P. M. Tetrahedron Lett. 1992, 33,    1549.-   26. 5 was synthesized by the method reported in: Buszek, K. R.;    Fang, F. G.; Forsyth, C. J; Jung, S. H.; Kishi, Y.; Scola, P. M.;    Yoon, S. K. Tetrahedron Lett. 1992, 33, 1553.-   27. Stamos, D. P.; Sheng, X. C.; Chen, S. S.; Kishi, Y. Tetrahedron    Lett. 1997, 38, 6355.-   28. 23 was synthesized by the method reported in: (a) Fang, F. G.;    Kishi, Y.; Matelich, M. C.; Scola, P. M. Tetrahedron Lett. 1992,    33, 1557. (b) Chen, C.-L.; Namba, K.; Kishi, Y. Org. Lett. 2009, 11,    409.-   29. Uemura, D.; Takahashi, K.; Yamamoto, T.; Katayama, C.; Tanaka,    J.; Okumura, Y.; Hirata, Y. J. Am. Chem. Soc. 1985, 107, 4796.

Other Embodiments

In the claims articles such as “a,” “an,” and “the” may mean one or morethan one unless indicated to the contrary or otherwise evident from thecontext. Claims or descriptions that include “or” between one or moremembers of a group are considered satisfied if one, more than one, orall of the group members are present in, employed in, or otherwiserelevant to a given product or process unless indicated to the contraryor otherwise evident from the context. The invention includesembodiments in which exactly one member of the group is present in,employed in, or otherwise relevant to a given product or process. Theinvention includes embodiments in which more than one, or all of thegroup members are present in, employed in, or otherwise relevant to agiven product or process.

Furthermore, the invention encompasses all variations, combinations, andpermutations in which one or more limitations, elements, clauses, anddescriptive terms from one or more of the listed claims is introducedinto another claim. For example, any claim that is dependent on anotherclaim can be modified to include one or more limitations found in anyother claim that is dependent on the same base claim. Where elements arepresented as lists, e.g., in Markush group format, each subgroup of theelements is also disclosed, and any element(s) can be removed from thegroup. It should it be understood that, in general, where the invention,or aspects of the invention, is/are referred to as comprising particularelements and/or features, certain embodiments of the invention oraspects of the invention consist, or consist essentially of, suchelements and/or features. For purposes of simplicity, those embodimentshave not been specifically set forth in haec verba herein. It is alsonoted that the terms “comprising” and “containing” are intended to beopen and permits the inclusion of additional elements or steps. Whereranges are given, endpoints are included. Furthermore, unless otherwiseindicated or otherwise evident from the context and understanding of oneof ordinary skill in the art, values that are expressed as ranges canassume any specific value or sub-range within the stated ranges indifferent embodiments of the invention, to the tenth of the unit of thelower limit of the range, unless the context clearly dictates otherwise.

This application refers to various issued patents, published patentapplications, journal articles, and other publications, all of which areincorporated herein by reference. If there is a conflict between any ofthe incorporated references and the instant specification, thespecification shall control. In addition, any particular embodiment ofthe present invention that falls within the prior art may be explicitlyexcluded from any one or more of the claims. Because such embodimentsare deemed to be known to one of ordinary skill in the art, they may beexcluded even if the exclusion is not set forth explicitly herein. Anyparticular embodiment of the invention can be excluded from any claim,for any reason, whether or not related to the existence of prior art.

Those skilled in the art will recognize or be able to ascertain using nomore than routine experimentation many equivalents to the specificembodiments described herein. The scope of the present embodimentsdescribed herein is not intended to be limited to the above Description,but rather is as set forth in the appended claims. Those of ordinaryskill in the art will appreciate that various changes and modificationsto this description may be made without departing from the spirit orscope of the present invention, as defined in the following claims.

What is claimed is:
 1. A compound of Formula (I):

or a pharmaceutically acceptable salt thereof, wherein R^(P1), R^(P2),and R^(P3) are each independently hydrogen, substituted or unsubstitutedalkyl, or an oxygen protecting group; R¹, R², R³, and R⁵ are eachindependently hydrogen, halogen, or substituted or unsubstituted alkyl;each instance of R⁴ is independently is hydrogen, halogen, substitutedor unsubstituted alkyl, or two R⁴ groups can be taken together to form a

group; each instance of R⁶ is independently is hydrogen, halogen,substituted or unsubstituted alkyl, or two R⁶ groups can be takentogether to form a

group; R^(X) is —OR^(X1), wherein R^(X1) is hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group; R^(Y) is —OR^(Y1),wherein R^(Y1) is hydrogen, substituted or unsubstituted alkyl, or anoxygen protecting group; and R^(X) and R^(Y) can be taken with theirintervening atoms to form a substituted or unsubstituted heterocyclicring.
 2. A compound of claim 1, wherein the compound is of formula:

or a pharmaceutically acceptable salt thereof.
 3. A compound of Formula(A-1):

or a pharmaceutically acceptable salt thereof, wherein R^(P17), R^(P18),and R^(P19) are each independently hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group; R^(Z1) is—CO₂R^(Z1a), wherein R^(Z1a) is hydrogen, substituted or unsubstitutedalkyl, or an oxygen protecting group; and X^(A) is hydrogen or ahalogen.
 4. A compound of Formula (B-1):

or a pharmaceutically acceptable salt thereof, wherein R^(P17) andR^(P18) are each independently hydrogen, substituted or unsubstitutedalkyl, or an oxygen protecting group; R^(Z1) is —CO₂R^(Z1a), whereinR^(Z1a) is hydrogen, substituted or unsubstituted alkyl, or an oxygenprotecting group; R^(Z2) is a halogen or a leaving group; and R^(Z3) isa halogen.
 5. A compound of Formula (C-1):

or a pharmaceutically acceptable salt thereof, wherein R^(Z1) is—CO₂R^(Z1a), wherein R^(Z1a) is hydrogen, substituted or unsubstitutedalkyl, or an oxygen protecting group; R^(Z2) is a halogen or a leavinggroup; R^(Z3) is a halogen; R^(X) is —OR^(X1), wherein R^(X1) ishydrogen, substituted or unsubstituted alkyl, or an oxygen protectinggroup; R^(Y) is —OR^(Y1), wherein R^(Y1) is hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group; and R^(X) and R^(Y)can be taken with their intervening atoms to form a substituted orunsubstituted heterocyclic ring.
 6. A compound of Formula (D-1):

or a pharmaceutically acceptable salt thereof, wherein R^(Z1) is—CO₂R^(Z1a), wherein R^(Z1a) is hydrogen, substituted or unsubstitutedalkyl, or an oxygen protecting group; R^(z4) is —CH₂OR^(Z4a) or —CHO,wherein R^(Z4a) is hydrogen, substituted or unsubstituted alkyl, or anoxygen protecting group; R^(P4) and R^(P5) are each independentlyhydrogen, substituted or unsubstituted alkyl, or an oxygen protectinggroup; R³ and R⁵ are each independently hydrogen, halogen, orsubstituted or unsubstituted alkyl; each instance of R⁴ is independentlyis hydrogen, halogen, substituted or unsubstituted alkyl, or two R⁴groups can be taken together to form a

group; each instance of R⁶ is independently hydrogen, halogen,substituted or unsubstituted alkyl, or two R⁶ groups can be takentogether to form a

group; R^(X) is —OR^(X1), wherein R^(X1) is hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group; R^(Y) is —OR^(Y1),wherein R^(Y1) is hydrogen, substituted or unsubstituted alkyl, or anoxygen protecting group; and R^(X) and R^(Y) can be taken with theirintervening atoms to form a substituted or unsubstituted heterocyclicring.
 7. A compound of Formula (E-1):

or a pharmaceutically acceptable salt thereof, wherein R^(Z4) is—CH₂OR^(Z4a) or —CHO, wherein R^(Z4a) is hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group; R^(P4) is hydrogen,substituted or unsubstituted alkyl, or an oxygen protecting group; R³and R⁵ are each independently hydrogen, halogen, or substituted orunsubstituted alkyl; each instance of R⁴ is independently is hydrogen,halogen, substituted or unsubstituted alkyl, or two R⁴ groups can betaken together to form a

group; each instance of R⁶ is independently hydrogen, halogen,substituted or unsubstituted alkyl, or two R⁶ groups can be takentogether to form a

group; R^(X) is —OR^(X1), wherein R^(X1) is hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group; R^(Y) is —OR^(Y1),wherein R^(Y1) is hydrogen, substituted or unsubstituted alkyl, or anoxygen protecting group; and R^(X) and R^(Y) can be taken with theirintervening atoms to form a substituted or unsubstituted heterocyclicring.
 8. A compound of Formula (F-1):

or a pharmaceutically acceptable salt thereof, wherein R^(P1), R^(P2),R^(P3), R^(P4), R^(P6), and R^(P7) are each independently hydrogen,substituted or unsubstituted alkyl, or an oxygen protecting group; R¹,R², R³, and R⁵ are each independently hydrogen, halogen, or substitutedor unsubstituted alkyl; each instance of R⁴ is independently ishydrogen, halogen, substituted or unsubstituted alkyl, or two R⁴ groupscan be taken together to form a

group; each instance of R⁶ is independently hydrogen, halogen,substituted or unsubstituted alkyl, or two R⁶ groups can be takentogether to form a

group; R^(X) is —OR^(X1), wherein R^(X1) is hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group; R^(Y) is —OR^(Y1),wherein R^(Y1) is hydrogen, substituted or unsubstituted alkyl, or anoxygen protecting group; and R^(X) and R^(Y) can be taken with theirintervening atoms to form a substituted or unsubstituted heterocyclicring.
 9. A compound of Formula (II):

or a pharmaceutically acceptable salt thereof, wherein R^(P8) ishydrogen, substituted or unsubstituted alkyl, or an oxygen protectinggroup; R¹, R², R³, and R⁵ are each independently hydrogen, halogen, orsubstituted or unsubstituted alkyl; each instance of R⁴ is independentlyis hydrogen, halogen, substituted or unsubstituted alkyl, or two R⁴groups can be taken together to form a

group; each instance of R⁶ is independently hydrogen, halogen,substituted or unsubstituted alkyl, or two R⁶ groups can be takentogether to form a

group; R⁷ is hydrogen, substituted or unsubstituted alkyl, or an oxygenprotecting group; R^(X) is —OR^(X1), wherein R^(X1) is hydrogen,substituted or unsubstituted alkyl, or an oxygen protecting group; R^(Y)is —OR^(Y1), wherein R^(Y1) is hydrogen, substituted or unsubstitutedalkyl, or an oxygen protecting group; and R^(X) and R^(Y) can be takenwith their intervening atoms to form a substituted or unsubstitutedheterocyclic ring; provided that a compound of Formula (II) is notnorhalichondrin A:


10. A compound of Formula (G-1):

or a pharmaceutically acceptable salt thereof, wherein R^(P8), R^(P9),R¹⁰, and R^(P11) are each independently hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group; R¹, R², R³, and R⁵are each independently hydrogen, halogen, or substituted orunsubstituted alkyl; each instance of R⁴ is independently is hydrogen,halogen, substituted or unsubstituted alkyl, or two R⁴ groups can betaken together to form a

group; each instance of R⁶ is independently hydrogen, halogen,substituted or unsubstituted alkyl, or two R⁶ groups can be takentogether to form a

group; R⁷ is hydrogen, substituted or unsubstituted alkyl, or an oxygenprotecting group; R^(X) is —OR^(X1), wherein R^(X1) is hydrogen,substituted or unsubstituted alkyl, or an oxygen protecting group; R^(Y)is —OR^(Y1), wherein R^(Y1) is hydrogen, substituted or unsubstitutedalkyl, or an oxygen protecting group; and R^(X) and R^(Y) can be takenwith their intervening atoms to form a substituted or unsubstitutedheterocyclic ring.
 11. A compound of Formula (III):

or a pharmaceutically acceptable salt thereof, wherein R^(P12) andR^(P13) are each independently hydrogen, substituted or unsubstitutedalkyl, or an oxygen protecting group; R¹, R², R³, and R⁵ are eachindependently hydrogen, halogen, or substituted or unsubstituted alkyl;each instance of R⁴ is independently is hydrogen, halogen, substitutedor unsubstituted alkyl, or two R⁴ groups can be taken together to form a

group; each instance of R⁶ is independently hydrogen, halogen,substituted or unsubstituted alkyl, or two R⁶ groups can be takentogether to form a

group; R^(X) is —OR^(X1), wherein R^(X1) is hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group; R^(Y) is —OR^(Y1),wherein R^(Y1) is hydrogen, substituted or unsubstituted alkyl, or anoxygen protecting group; and R^(X) and R^(Y) can be taken with theirintervening atoms to form a substituted or unsubstituted heterocyclicring; provided that a compound of Formula (III) is not homohalichondrinA:


12. A compound of Formula (H-1):

or a pharmaceutically acceptable salt thereof, wherein R^(P12), R^(P13),R^(P14), R^(P15) and R^(P16) are each independently hydrogen,substituted or unsubstituted alkyl, or an oxygen protecting group; R¹,R², R³, and R⁵ are each independently hydrogen, halogen, or substitutedor unsubstituted alkyl; each instance of R⁴ is independently ishydrogen, halogen, substituted or unsubstituted alkyl, or two R⁴ groupscan be taken together to form a

group; each instance of R⁶ is independently hydrogen, halogen,substituted or unsubstituted alkyl, or two R⁶ groups can be takentogether to form a

group; R^(X) is —OR^(X1), wherein R^(X1) is hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group; R^(Y) is —OR^(Y1),wherein R^(Y1) is hydrogen, substituted or unsubstituted alkyl, or anoxygen protecting group; and R^(X) and R^(Y) can be taken with theirintervening atoms to form a substituted or unsubstituted heterocyclicring.
 13. A compound of Formula (L-1):

or a pharmaceutically acceptable salt thereof, wherein R^(P12), R^(P13),R^(P14), and R^(P16) are each independently hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group; R¹ and R² are eachindependently hydrogen, halogen, or substituted or unsubstituted alkyl;and X is a halogen.
 14. The compound of any of claims 1 and 6-12,wherein two instances of R⁴ are taken together to form a

group.
 15. The compound of any of claims 1 and 6-12, wherein twoinstances of R⁶ are taken together to form a

group.
 16. The compound of any of claims 1 and 8-13, wherein R¹ ismethyl; and the carbon to which the methyl group is attached is in the(R)- or (S)-configuration.
 17. The compound of any of claims 1 and 8-13,wherein R²is methyl; and the carbon to which the methyl group isattached is in the (R)- or (S)-configuration.
 18. The compound of any ofclaims 1 and 8-12, wherein R³ is methyl; and the carbon to which themethyl group is attached is in the (R)- or (S)-configuration.
 19. Thecompound of any of claims 1 and 8-12, wherein R⁵ is methyl; and thecarbon to which the methyl group is attached is in the (R)- or(S)-configuration.
 20. The compound of any of claims 1 and 8-12, whereinall of R¹, R², R³, and R⁵ are methyl; and the carbon to which the eachmethyl group is attached is independently in the (R)- or(S)-configuration.
 21. The compound of claim 4 or 5, wherein R^(Z2) ischlorine.
 22. The compound of claim 4 or 5, wherein R^(Z3) is bromine.23. The compound of claim 3, wherein X^(A) is iodine.
 24. The compoundof any of claims 1 and 5-12, wherein R^(X) is a hydroxyl; and the carbonto which the hydroxyl group is attached is in the (R)- or(S)-configuration.
 25. The compound of any of claims 1 and 5-12, whereinR^(Y) is a hydroxyl; and the carbon to which the hydroxyl group isattached is in the (R)- or (S)-configuration.
 26. The compound of any ofclaims 1 and 5-12, wherein R^(X) and R^(Y) are taken with theirintervening atoms to form a substituted or unsubstituted 5-6 memberedheterocyclic ring.
 27. The compound of any of claims 1, 3, 4, and 6-13,wherein all of R^(P1), R^(P2), R^(P3), R^(P4), R^(P5), R^(P6), R^(P7),R^(P8), R^(P9), R^(P10), R^(P11), R^(P12), R^(P13), R^(P14), R^(P15),R^(P16), R^(P17), R^(P18), and R^(P19) are independently hydrogen,t-butyldimethyl silyl, acetyl, p-methoxybenzyl, or p-methoxyphenyl. 28.The compound of any of claims 3-6, wherein R^(Z1) is —-CO₂Me.
 29. Thecompound of claim 6 or 7, wherein R^(Z4) is —CH₂OR^(Z4a); and R^(Z4a) ishydrogen or t-butyldimethyl silyl.
 30. The compound of claim 9 or 10,wherein R⁷ is -Me.
 31. The compound of any of claims 1, 2, 9, 11, 15-20,24-27, and 30, wherein the carbon to which the C38 ketal is attached isin the (S)-configuration.
 32. The compound of any of claims 1, 2, 9, 11,15-20, 24-27, and 30, wherein the carbon to which the C38 ketal isattached is in the (R)-configuration.
 33. A method of preparing acompound of claim 1 of Formula (I), the method comprising: cyclizing acompound of Formula (F-1):

or a salt thereof, wherein R^(P1), R^(P2), R^(P3), R^(P4), R^(P6), andR^(P7) are each independently hydrogen, substituted or unsubstitutedalkyl, or an oxygen protecting group; R¹, R², R³, and R⁵ are eachindependently hydrogen, halogen, or substituted or unsubstituted alkyl;each instance of R⁴ is independently is hydrogen, halogen, substitutedor unsubstituted alkyl, or two R⁴ groups can be taken together to form a

group; each instance of R⁶ is independently hydrogen, halogen,substituted or unsubstituted alkyl, or two R⁶ groups can be takentogether to form a

group; R^(X) is —OR^(X1), wherein R^(X1) is hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group; R^(Y) is —OR^(Y1),wherein R^(Y1) is hydrogen, substituted or unsubstituted alkyl, or anoxygen protecting group; and R^(X) and R^(Y) can be taken with theirintervening atoms to form a substituted or unsubstituted heterocyclicring, under sufficient conditions to provide a compound of Formula (I)of claim 1 and optionally protecting or deprotecting a compound ofFormula (I) of claim
 1. 34. The method of claim 33 further comprisingthe steps of: joining a compound of Formula (E-1):

wherein R^(Z4) is —CH₂OR^(Z4a) or —CHO, wherein R^(Z4a) is hydrogen,substituted or unsubstituted alkyl, or an oxygen protecting group;R^(P4) is hydrogen, substituted or unsubstituted alkyl, or an oxygenprotecting group; R³ and R⁵ are each independently hydrogen, halogen, orsubstituted or unsubstituted alkyl; each instance of R⁴ is independentlyis hydrogen, halogen, substituted or unsubstituted alkyl, or two R⁴groups can be taken together to form a

group; each instance of R⁶ is independently hydrogen, halogen,substituted or unsubstituted alkyl, or two R⁶ groups can be takentogether to form a

group; R^(X) is —OR^(X1), wherein R^(X1) is hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group; R^(Y) is —OR^(Y1),wherein R^(Y1) is hydrogen, substituted or unsubstituted alkyl, or anoxygen protecting group; and R^(X) and R^(Y) can be taken with theirintervening atoms to form a substituted or unsubstituted heterocyclicring, with a compound of Formula (I-1):

wherein R^(P1), R^(P2), R^(P3), R^(P6) and R^(P7) is hydrogen,substituted or unsubstituted alkyl, or an oxygen protecting group; R³and R⁵ are each independently hydrogen, halogen, or substituted orunsubstituted alkyl; R¹ and R² are each independently hydrogen, halogen,or substituted or unsubstituted alkyl; and X is a halogen, undersufficient conditions to provide a compound of Formula (F-1) andoptionally protecting or deprotecting a compound of Formula (F-1).
 35. Amethod of preparing a compound of claim 9 of Formula (II) ornorhalichondrin A, the method comprising: cyclizing a compound ofFormula (G-1):

or a salt thereof, wherein R^(P8), R^(P9), R^(P10), and R^(P11) are eachindependently hydrogen, substituted or unsubstituted alkyl, or an oxygenprotecting group; R¹, R², R³, and R⁵ are each independently hydrogen,halogen, or substituted or unsubstituted alkyl; each instance of R⁴ isindependently is hydrogen, halogen, substituted or unsubstituted alkyl,or two R⁴ groups can be taken together to form a

group; each instance of R⁶ is independently hydrogen, halogen,substituted or unsubstituted alkyl, or two R⁶ groups can be takentogether to form a

group; R⁷ is hydrogen, substituted or unsubstituted alkyl, or an oxygenprotecting group; R^(X) is —OR^(X1), wherein R^(X1) is hydrogen,substituted or unsubstituted alkyl, or an oxygen protecting group; R^(Y)is —OR^(Y1), wherein R^(Y1) is hydrogen, substituted or unsubstitutedalkyl, or an oxygen protecting group; and R^(X) and R^(Y) can be takenwith their intervening atoms to form a substituted or unsubstitutedheterocyclic ring, under sufficient conditions to provide a compound ofFormula (II) of claim 9 or norhalichondrin A and optionally protectingor deprotecting a compound of Formula (II) of claim 9 or norhalichondrinA.
 36. The method of claim 35 further comprising the steps of: joining acompound of Formula (E-1):

wherein R^(Z4) is —CH₂OR^(Z4a) or —CHO, wherein R^(Z4a) is hydrogen,substituted or unsubstituted alkyl, or an oxygen protecting group;R^(P4) is hydrogen, substituted or unsubstituted alkyl, or an oxygenprotecting group; R³ and R⁵ are each independently hydrogen, halogen, orsubstituted or unsubstituted alkyl; each instance of R⁴ is independentlyis hydrogen, halogen, substituted or unsubstituted alkyl, or two R⁴groups can be taken together to form a

group; each instance of R⁶ is independently hydrogen, halogen,substituted or unsubstituted alkyl, or two R⁶ groups can be takentogether to form a

group; R^(X) is —OR^(X1), wherein R^(X1) is hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group; R^(Y) is —OR^(Y1),wherein R^(Y1) is hydrogen, substituted or unsubstituted alkyl, or anoxygen protecting group; and R^(X) and R^(Y) can be taken with theirintervening atoms to form a substituted or unsubstituted heterocyclicring, with a compound of Formula (K-1):

wherein R^(P8), R^(P9), and R^(P10) are each independently hydrogen,substituted or unsubstituted alkyl, or an oxygen protecting group; R¹and R² are each independently hydrogen, halogen, or substituted orunsubstituted alkyl; R⁷ is hydrogen, substituted or unsubstituted alkyl,or an oxygen protecting group; and X is a halogen, under sufficientconditions to provide a compound of Formula (G-1) and optionallyprotecting or deprotecting a compound of Formula (G-1).
 37. A method ofpreparing a compound of claim 11 of Formula (III) or homohalichondrin A,the method comprising: cyclizing a compound of Formula (H-1):

or a salt thereof, wherein wherein R^(P12), R^(P13), R^(P14), R^(P15)and R^(P16) are each independently hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group; R¹, R², R³, and R⁵are each independently hydrogen, halogen, or substituted orunsubstituted alkyl; each instance of R⁴ is independently is hydrogen,halogen, substituted or unsubstituted alkyl, or two R⁴ groups can betaken together to form a

group; each instance of R⁶ is independently hydrogen, halogen,substituted or unsubstituted alkyl, or two R⁶ groups can be takentogether to form a

group; R^(X) is —OR^(X1), wherein R^(X1) is hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group; R^(Y) is —OR^(Y1),wherein R^(Y1) is hydrogen, substituted or unsubstituted alkyl, or anoxygen protecting group; and R^(X) and R^(Y) can be taken with theirintervening atoms to form a substituted or unsubstituted heterocyclicring, under sufficient conditions to provide a compound of Formula (III)of claim 11 or homohalichondrin A and optionally protecting ordeprotecting a compound of Formula (III) of claim 11 or homohalichondrinA.
 38. The method of claim 37 further comprising the steps of: joining acompound of Formula (E-1):

wherein R^(Z4) is —CH₂OR^(Z4a) or —CHO, wherein R^(Z4a) is hydrogen,substituted or unsubstituted alkyl, or an oxygen protecting group;R^(P4) is hydrogen, substituted or unsubstituted alkyl, or an oxygenprotecting group; R³ and R⁵ are each independently hydrogen, halogen, orsubstituted or unsubstituted alkyl; each instance of R⁴ is independentlyis hydrogen, halogen, substituted or unsubstituted alkyl, or two R⁴groups can be taken together to form a

group; each instance of R⁶ is independently hydrogen, halogen,substituted or unsubstituted alkyl, or two R⁶ groups can be takentogether to form a

group; R^(X) is —OR^(X1), wherein R^(X1) is hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group; R^(Y) is —OR^(Y1),wherein R^(Y1) is hydrogen, substituted or unsubstituted alkyl, or anoxygen protecting group; and R^(X) and R^(Y) can be taken with theirintervening atoms to form a substituted or unsubstituted heterocyclicring, with a compound of Formula (L-1):

wherein R^(P12), R^(P13), R^(P14), and R^(P16) are each independentlyhydrogen, substituted or unsubstituted alkyl, or an oxygen protectinggroup; R¹ and R² are each independently hydrogen, halogen, orsubstituted or unsubstituted alkyl; and X is a halogen, under sufficientconditions to provide a compound of Formula (H-1) and optionallyprotecting or deprotecting a compound of Formula (H-1).
 39. The methodof any of claims 34, 36, and 38 further comprising the steps of:cyclizing a compound of Formula (D-1):

wherein R^(Z1) is —CO₂R^(Z1a), wherein R^(Z1a) is hydrogen, substitutedor unsubstituted alkyl, or an oxygen protecting group; R^(Z4) is—CH₂OR^(Z4a) or —CHO, wherein R^(Z4a) is hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group; R^(P4) and R^(P5)are each independently hydrogen, substituted or unsubstituted alkyl, oran oxygen protecting group; R³ and R⁵ are each independently hydrogen,halogen, or substituted or unsubstituted alkyl; each instance of R⁴ isindependently is hydrogen, halogen, substituted or unsubstituted alkyl,or two R⁴ groups can be taken together to form a

group; each instance of R⁶ is independently hydrogen, halogen,substituted or unsubstituted alkyl, or two R⁶ groups can be takentogether to form a

group; R^(X) is —OR^(X1), wherein R^(X1) is hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group; R^(Y) is —OR^(Y1),wherein R^(Y1) is hydrogen, substituted or unsubstituted alkyl, or anoxygen protecting group; and R^(X) and R^(Y) can be taken with theirintervening atoms to form a substituted or unsubstituted heterocyclicring, under sufficient conditions to provide a compound of Formula (E-1)and optionally protecting or deprotecting a compound of Formula (E-1).40. The method of claim 39 further comprising the steps of: joining acompound of Formula (C-1):

wherein R^(Z1) is —CO₂R^(Z1a), wherein R^(Z1a) is hydrogen, substitutedor unsubstituted alkyl, or an oxygen protecting group; R^(Z2) is ahalogen or a leaving group; R^(Z3) is a halogen; R^(X) is —OR^(X1),wherein R^(X1) is hydrogen, substituted or unsubstituted alkyl, or anoxygen protecting group; R^(Y) is —OR^(Y1), wherein R^(Y1) is hydrogen,substituted or unsubstituted alkyl, or an oxygen protecting group; andR^(X) and R^(Y) can be taken with their intervening atoms to form asubstituted or unsubstituted heterocyclic ring, with a compound ofFormula (J-1):

wherein R^(Z5) is —CH₂OR^(Z5a) or —CHO, wherein R^(Z5a) is hydrogen,substituted or unsubstituted alkyl, or an oxygen protecting group;R^(Z4) is —CH₂OR^(Z4a) or —CHO, wherein R^(Z4a) is hydrogen, substitutedor unsubstituted alkyl, or an oxygen protecting group; R^(P4) and R^(P5)are each independently hydrogen, substituted or unsubstituted alkyl, oran oxygen protecting group; R³ and R⁵ are each independently hydrogen,halogen, or substituted or unsubstituted alkyl; and each instance of R⁴is independently is hydrogen, halogen, substituted or unsubstitutedalkyl, or two R⁴ groups can be taken together to form a

group, under sufficient conditions to provide a compound of Formula(D-1) and optionally protecting or deprotecting a compound of Formula(D-1).
 41. The method of claim 40 further comprising the steps of:cyclizing a compound of Formula (B-1):

wherein R^(P17) and R^(P18) are each independently hydrogen, substitutedor unsubstituted alkyl, or an oxygen protecting group; R^(Z1) is—CO₂R^(Z1a), wherein R^(Z1a) is hydrogen, substituted or unsubstitutedalkyl, or an oxygen protecting group; R^(Z2) is a halogen or a leavinggroup; and R^(Z3) is a halogen, under sufficient conditions to provide acompound of Formula (C-1) and optionally protecting or deprotecting acompound of Formula (C-1).
 42. The method of claim 41 further comprisingthe steps of: joining a compound of Formula (A-1):

wherein R^(P17), R^(P18), and R^(P19) are each independently hydrogen,substituted or unsubstituted alkyl, or an oxygen protecting group;R^(Z1) is —CO₂R^(Z1a), wherein R^(Z1a) is hydrogen, substituted orunsubstituted alkyl, or an oxygen protecting group; and X^(A) ishydrogen or a halogen, with a compound of formula:

wherein R^(Z2) is a halogen or a leaving group; and R^(Z3) is a halogen,under sufficient conditions to provide a compound of Formula (B-1) andoptionally protecting or deprotecting a compound of Formula (B-1).
 43. Acompound selected from the following group:


44. A method of preparing a compound of claim 43 or C38epi-homohalichondrin B

the method comprising: preparing a solution of the C38 epimeric compoundin an organic solvent; and contacting the compound with an acid, undersufficient conditions to provide the compound of claim 43 or C38epi-homohalichondrin B.
 45. A method of preparing a compound selectedfrom the following group:

the method comprising: preparing a solution of the C38 epimeric compoundin an organic solvent; and contacting the compound with an acid, undersufficient conditions to provide the compound.
 46. A method ofinterconverting a compound of any of claims 1, 2, 9, 11, 14-20, 24-27,31, and 32 with its C38 epimer, the method comprising: preparing asolution of the compound in an organic solvent; and contacting thecompound with an acid, under sufficient conditions to provide theepimeric compound.
 47. The method of claim 44-46, wherein the organicsolvent is dichloromethane, diethylether, acetonitrile, or methanol. 48.The method of claim 44-46, wherein the acid is pyridiniump-toluenesulfonate, camphorsulfonic acid, or trimethylsilyltrifluoromethanesulfonate.
 49. The method of claim 44-46, furthercomprising the step of cooling the reaction mixture.
 50. Apharmaceutical composition comprising a compound of claims 1-32 and 43,or a pharmaceutically acceptable salt thereof, and optionally apharmaceutically acceptable excipient.
 51. A method of inhibitingmitosis in a subject in need thereof, the method comprisingadministering to the subject a compound of any one of the precedingclaims, or a pharmaceutically acceptable salt thereof, or apharmaceutical composition of claim 50, in an amount sufficient toinhibit mitosis.
 52. A method of triggering apoptosis in cell of asubject, the method comprising administering to the subject a compoundof any one of the preceding claims, or a pharmaceutically acceptablesalt thereof, or a pharmaceutical composition of claim 50, in an amountsufficient to trigger apoptosis.
 53. A method of treating a conditionassociated with aberrant cell proliferation in a subject in needthereof, the method comprising administering to the subject a compoundof any one of the preceding claims, or a pharmaceutically acceptablesalt thereof, or a pharmaceutical composition of claim 50, in an amountsufficient to treat the condition.
 54. The method of claims 51-53,wherein a compound of any of the preceeding claims binds tomicrotubules.
 55. The method of claims 51-53, wherein a compound of anyof the preceeding claims binds to high affinity sites at the plus endsof existing microtubules.
 56. The method of claims 51-53, wherein acompound of any of the preceeding claims is an inhibitor of microtubuledynamics.
 57. The method of any one claims 51-56, wherein the conditionis a proliferative disease.
 58. The method of claim 57, wherein thecondition is metastatic breast cancer, non-small cell lung cancer,prostate cancer, or a sarcoma.
 59. A kit comprising: a compound of anyone claims 1-32 and 43, or a pharmaceutically acceptable salt thereof,or a pharmaceutical composition of claim 50; a container; andinstructions for using the kit.